late 14c., senten, originally a hunting term, "to find the scent of, perceive by smell," from Old French sentir "to feel, smell, touch, taste; realize, perceive; make love to," from Latin sentire " to feel, perceive by the senses; give one's opinion or sentiments" (see sense (n.)).
The unetymological -c- appeared 17c., perhaps in this case by influence of ascent, descent, etc., or by influence of science. But such an insertion was a pattern in early Modern English and also yielded scythe and for a time threatened to establish scite and scituate.
Figurative use from 1550s. The transitive sense "impregnate with an odor, make fragrant, perfume" is from 1690s. Related: Scented; scenting.