early 14c., ardaunt, specifically of alcoholic distillates, brandy, etc., "flammable," from Old French ardant "burning, hot; zealous" (13c.), from Latin ardentem (nominative ardens) "glowing, fiery, hot, ablaze," also used figuratively of passions, present participle of ardere "to burn" (from PIE root *as- "to burn, glow").
The figurative sense ("burning with passions, desire, etc.") is from late 14c.; the general etymological sense of "burning, parching" (c. 1400) remains rare. Ardent spirits (late 15c.) retains the oldest English meaning, but the term now, if used at all, probably is felt in a figurative, causative sense. Related: Ardently.
mid-15c., "foolish person," of unknown origin, perhaps related to obsolete verb fop "make a fool of," from a continental source akin to German foppen "jeer at, make a fool of." Sense of "dandy, coxcomb, man ostentatiously nice in manner and appearance" is from 1670s, perhaps given in derision by those who thought such things foolish. The 18c. was their period of greatest florescense. The junior variety was a fopling (1680s).
His was the sumptuous age of powder and patches. He was especially dainty in the matters of sword-knots, shoe-buckles, and lace ruffles. He was ablaze with jewelry, took snuff with an incomparable air out of a box studded with diamonds, and excelled in the "nice conduct of a clouded cane." [Charles J. Dunphie, "Fops and Foppery," New York, 1876]