Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.

WORD ORIGIN

slang, "clever, alert, wide awake," late 18c., perhaps from fly (n.) on the notion of the insect being hard to catch. Other theories, however, trace it to fledge or flash. Slang use in 1990s might be a revival or a reinvention.

MORE RELATED WORDS FOR FLY IN THE OINTMENT

Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.