a suffix forming adverbs from adjectives: gladly; gradually; secondly.See Grammar note at adverb.
a suffix meaning “every,” attached to certain nouns denoting units of time: hourly; daily.
an adjective suffix meaning “-like”: saintly; cowardly.

Origin of -ly

(adv.) Middle English -li, -lich(e), Old English -līce (-līc adj. suffix + -e adv. suffix); (adj.) Middle English -li, -ly, -lich(e), Old English -līc (cognate with German -lich), suffixal use of gelīc like1


3 See -ish1.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for -ly (1 of 2)



suffix forming adjectives

having the nature or qualities ofbrotherly; godly
occurring at certain intervals; everydaily; yearly

Word Origin for -ly

Old English -lic

British Dictionary definitions for -ly (2 of 2)



suffix forming adverbs

in a certain manner; to a certain degreequickly; recently; chiefly

Word Origin for -ly

Old English -lice, from -lic -ly 1
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