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.

c. 1400, sent, "a smell, what can be smelled" (especially a trace left by an animal in passing used as a means of pursuit by a hound), also "perception, sensation" (the etymological sense); from scent (v.). Often figurative, of pursuits or inquiries of any kind. Almost always applied to agreeable odors; the meaning "a perfume, fragrant liquid distilled from flowers, etc." is by late 15c. (Caxton).

1570s, "endowed with the power of smell," a sense now obsolete, past-participle adjective from scent (v.). By 1660s as "having a scent," 1740 as "perfumed."

"fragrant, emitting a smell or scent," early 15c., from Medieval Latin odorosus, from Latin odorus "having a smell," from odor "a smell, a scent" (see odor). Related: Odorously; odorousness.

mid-14c., "an odor," from Old French flaire "odor or scent," especially in hunting, "fragrance, sense of smell," from flairier "to give off an odor; stink; smell sweetly" (Modern French flairer), from Vulgar Latin *flagrare, a dissimilation of Latin fragrare "emit (a sweet) odor" (see fragrant). Sense of "special aptitude" is American English, 1925, probably from hunting and the notion of a hound's ability to track scent.

1530s, "to fill with smoke or vapor," from perfume (n.) or from French parfumer. Meaning "to impart a sweet scent to" is from 1530s. Related: Perfumed; perfuming.

c. 1300, "sweet smell, scent, fragrance," from Anglo-French odour, from Old French odor "smell, perfume, fragrance" (12c., Modern French odeur) and directly from Latin odor "a smell, a scent" (pleasant or disagreeable), from PIE root *hed- "to smell" (source also of Latin olere "emit a smell, to smell of," with Sabine -l- for -d-; Greek ozein "to smell," odmē "odor, scent;" Armenian hotim "I smell;" Lithuanian uodžiu, uosti "to smell, sniff;" Old Czech jadati "to investigate, explore").

Neutral sense of "smell as an inherent property of matter; scent or fragrance whether pleasant or not" is from late 14c. "[W]hen used without a qualifying adjunct, the word usually denotes an agreeable smell" [Century Dictionary, 1895]. Good or bad odor, in reference to repute or esteem, is from 1835. Odor of sanctity (1756) is from French odeur de sainteté (17c.) "sweet or balsamic scent said to be exhaled by the bodies of eminent saints at death or upon disinterment." In Middle English odor also had a figurative sense of "spiritual fragrance of Christ's sacrifice." 

early 15c., "sweet scent, fragrance," also figurative, from Old French redolence, redolens, which is related to redolent "emitting an odor" (see redolent) or from Medieval Latin redolentia.