"unwilling, strtuggling against duty or a command," 1660s, from Latin reluctantem (nominative reluctans), present participle of reluctari "to struggle against, resist, make opposition," from re- "against" (see re-) + luctari "to struggle, wrestle" (see reluctance). Related: Reluctantly. The Latin word also is the source of Spanish reluchante, Italian riluttante.
Reluctant, literally, struggling back from, implies some degree of struggle either with others who are inciting us on, or between our own inclination and some strong motive, as sense of duty, whether it operates as an impelling or as a restraining influence. [Century Dictionary]