reluctant: [17] To be reluctant about doing something is etymologically to ‘struggle against’ it. The word comes from the present participle of Latin reluctārī, a compound verb formed from the prefix re- ‘against’ and luctārī ‘struggle’. Among the first English writers to employ it was John Milton, who used it in the literal Latin sense, describing the writhing Satan: ‘a monstrous serpent on his belly prone, reluctant, but in vain’, Paradise Lost 1667. ‘Unwilling, averse’, a metaphorical extension which saw the light of day in Latin, made its debut in English at the start of the 18th century.
reluctant (adj.)
"unwilling," 1660s, from Latin reluctantem (nominative reluctans), present participle of reluctari (see reluctance). Related: Reluctantly. The Latin word is also the source of Spanish reluchante, Italian riluttante.