2、explicit:  Something that is explicit has literally been ‘unfolded’. Like the earlier borrowing explicate , the word comes from the past participle of Latin explicāre, a compound verb formed from the prefix ex- ‘un-’ and plicāre ‘fold’ (source of English ply and related to English fold). At first, in the 16th and 17th centuries, English retained the literal sense of the original, but gradually it dropped out in favour of the metaphorical ‘make clear, distinct, and open’ (already present in Latin).=> exploit, fold, ply
4、1610s,"open to the understanding, not obscure or ambiguous,"from French explicite, from Latin explicitus"unobstructed,"variant past participle of explicare"unfold, unravel, explain,"from ex-"out"(see ex-) + plicare"to fold"(see ply (v.1)). As a euphemism for"pornographic"it dates from 1971. Related: Explicitness."Explicitus"was written at the end of medieval books, originally short for explicitus est liber"the book is unrolled."