Imply, which is the same word, retains more of the original sense. Sense of "hire, engage" first recorded in English 1580s, from meaning "involve in a particular purpose," which arose in Late Latin. Related: Employed; employing; employable.
Meaning "to involve something unstated as a logical consequence" first recorded c. 1400; that of "to hint at" is from 1580s. Related: Implied; implying. The distinction between imply and infer is in "What do you imply by that remark?" but, "What am I to infer from that remark?" Or, as Century Dictionary puts it, "An action implies ability or preparation, but involves consequences."
1743, "a plea of having been elsewhere when an action took place," from Latin alibi (adv.) "elsewhere, somewhere else," locative of alius "another, other, different," from PIE root *al- (1) "beyond." The weakened sense of "excuse" is attested since 1912, but technically any proof of innocence that doesn't involve being "elsewhere" is an excuse (n.) and not an alibi.
1620s, "to intertwine," from Latin complicatus "folded together; confused, intricate," past participle of complicare "to involve," literally "to fold together," from com "with, together" (see com-) + plicare "to fold, weave" (from PIE root *plek- "to plait"). Meaning "to make more complex or intricate" is recorded from 1832, from earlier sense "to combine in a complex way" (17c.). Related: Complicated; complicating.
1530s, originally in the figurative sense of "entangle, involve;" the literal transitive sense of "to catch in a net, entangle" is from 1540s; from mesh (n.). Literal sense "to become enmeshed" is from 1580s. Intransitive sense of "become engaged," as the teeth of one wheel with those of another, is by 1850. The figurative sense of "to fit in, combine" is by 1944. Related: Meshed; meshing.
1590s, "implied, resting on inference," from French implicite and directly from Latin implicitus, later variant of implicatus "entangled, confused, involved," past participle of implicare "entangle, involve," from assimilated form of in- "into, in, on, upon" (from PIE root *en "in") + plicare "to fold" (from PIE root *plek- "to plait"). From c. 1600 as "resulting from perfect confidence (in authority), unquestioning" (especially of faith).
