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only

[ohn-lee]
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adverb
  1. without others or anything further; alone; solely; exclusively: This information is for your eyes only.
  2. no more than; merely; just: If it were only true! I cook only on weekends.
  3. as recently as: I read that article only yesterday.
  4. in the final outcome or decision: You will only regret your harsh words to me.
adjective
  1. being the single one or the relatively few of the kind: This is the only pencil I can find.
  2. having no sibling or no sibling of the same sex: an only child; an only son.
  3. single in superiority or distinction; unique; the best: the one and only Muhammad Ali.
conjunction
  1. but (introducing a single restriction, restraining circumstance, or the like): I would have gone, only you objected.
  2. Older Use. except; but: Only for him you would not be here.
Idioms
  1. only too,
    1. as a matter of fact; extremely: I am only too glad to go.
    2. unfortunately; very: It is only too likely to happen.

Origin of only

before 900; Middle English; Old English ānlich, ǣnlich. See one, -ly

Synonyms

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5. solitary, lone. 7. peerless; exclusive.

Antonyms

5. plentiful, common.

Usage note

The placement of only as a modifier is more a matter of style and clarity than of grammatical rule. In a sentence like The doctor examined the children, varying the placement of only results in quite different meanings: The doctor only examined the children means that the doctor did nothing else. And The doctor examined only the children means that no one else was examined. Especially in formal writing, the placement of only immediately before what it modifies is often observed: She sold the stock only because she needed the money. However, there has long been a tendency in all varieties of speech and writing to place only before the verb ( She only sold the stock because she needed the money ), and such placement is rarely confusing.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for only too

only

adjective (prenominal)
  1. the only being single or very few in numberthe only men left in town were too old to bear arms
  2. (of a child) having no siblings
  3. unique by virtue of being superior to anything else; peerless
  4. one and only
    1. (adjective)incomparable; unique
    2. (as noun)the object of all one's loveyou are my one and only
adverb
  1. without anyone or anything else being included; aloneyou have one choice only; only a genius can do that
  2. merely or justit's only Henry
  3. no more or no greater thanwe met only an hour ago
  4. Irish (intensifier)she was only marvellous; it was only dreadful
  5. used in conditional clauses introduced by if to emphasize the impossibility of the condition ever being fulfilledif I had only known, this would never have happened
  6. not earlier than; not…untilI only found out yesterday
  7. if only an expression used to introduce a wish, esp one felt to be unrealizable
  8. only if never…except when
  9. only too
    1. (intensifier)he was only too pleased to help
    2. most regrettably (esp in the phrase only too true)
sentence connector
  1. but; however: used to introduce an exception or conditionplay outside: only don't go into the street

Word Origin

Old English ānlīc, from ān one + -līc -ly ²

usage

In informal English, only is often used as a sentence connector: I would have phoned you, only I didn't know your number. This use should be avoided in formal writing: I would have phoned you if I'd known your number. In formal speech and writing, only is placed directly before the word or words that it modifies: she could interview only three applicants in the morning. In all but the most formal contexts, however, it is generally regarded as acceptable to put only before the verb: she could only interview three applicants in the morning. Care must be taken not to create ambiguity, esp in written English, in which intonation will not, as it does in speech, help to show to which item in the sentence only applies. A sentence such as she only drinks tea in the afternoon is capable of two interpretations and is therefore better rephrased either as she drinks only tea in the afternoon (i.e. no other drink) or she drinks tea only in the afternoon (i.e. at no other time)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for only too

only

adj.

Old English ænlic, anlic "only, unique, solitary," literally "one-like," from an "one" (see one) + -lic "-like" (see -ly (1)). Use as an adverb and conjunction developed in Middle English. Distinction of only and alone (now usually in reference to emotional states) is unusual; in many languages the same word serves for both. German also has a distinction in allein/einzig. Phrase only-begotten (mid-15c.) is biblical, translating Latin unigenitus, Greek monogenes. The Old English form was ancenned.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with only too

only too

1

At the very least, as a matter of fact, as in I know only too well that I can't win the lottery. This usage was first recorded in 1817.

2

Very, extremely, as in I am only too glad to help. This usage was first recorded in 1899.

only

In addition to the idioms beginning with only

also see:

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.