"advantageous," early 15c., present-participle adjective from avail (v.). Related: Availingly.
Entries linking to availing
avail v.
c. 1300, availen, "to help (someone), assist; benefit, be profitable to; be for the advantage of; have force or efficacy, serve for a purpose," apparently an Anglo-French compound of Old French a- "to" (see ad-) + vaill-, present stem of valoir "be worth," from Latin valere "be strong, be worth" (from PIE root *wal- "to be strong"). Related: Availed; availing. As a noun, from c. 1400.
unavailing adj.
"ineffectual, useless," 1660s, from un- (1) "not" + availing. Also see unavailable.