adjective (used predicatively)
- to allow (someone) to be by himself or herself: Leave him alone—he wants to rest.
- to refrain from annoying or interfering with: The youngsters wouldn't leave the dog alone, and he finally turned on them.
- to refrain from annoying or interfering with.
- not to mention: He was too tired to walk, let alone run.
British Dictionary definitions for let alone
adjective, adverb (postpositive)
Word Origin for alone
Word Origin and History for let alone
c.1300 contraction of all ane, from Old English all ana "unaccompanied, all by oneself," from all "all, wholly" (see all) + an "one" (see one). Similar compounds are found in German (allein) and Dutch (alleen).
Idioms and Phrases with let alone (1 of 2)
See leave someone alone.
Not to mention, as in We have no room for another house guest, let alone an entire family. [c. 1800]
Idioms and Phrases with let alone (2 of 2)
see go it alone; leave someone alone; leave well enough alone; let alone.