Words related to insensible

in- (1)
Origin and meaning of in-
word-forming element meaning "not, opposite of, without" (also im-, il-, ir- by assimilation of -n- with following consonant, a tendency which began in later Latin), from Latin in- "not," cognate with Greek an-, Old English un-, all from PIE root *ne- "not."

In Old French and Middle English often en-, but most of these forms have not survived in Modern English, and the few that do (enemy, for instance) no longer are felt as negative. The rule of thumb in English has been to use in- with obviously Latin elements, un- with native or nativized ones.
sensible (adj.)
late 14c., "capable of sensation or feeling;" also "capable of being sensed or felt, perceptible to the senses," hence "easily understood; logical, reasonable," from Late Latin sensibilis "having feeling: perceptible by the senses," from sensus, past participle of sentire "perceive, feel" (see sense (n.)). Of persons, "aware, cognizant (of something)" early 15c.; "having good sense, capable of reasoning, discerning, clever," mid-15c. Of clothes, shoes, etc., "practical rather than fashionable" it is attested from 1855.

Other Middle English senses included "susceptible to injury or pain" (early 15c., now gone with sensitive); "worldly, temporal, outward" (c. 1400); "carnal, unspiritual" (early 15c., now gone with sensual). Related: Sensibleness.
insensate (adj.)

1510s, "lacking or deprived of physical senses," from Late Latin insensatus "irrational, foolish," from in- "not" (see in- (1)) + sensatus "gifted with sense" (see sensate).

Meaning "irrational, maniacal, lacking or deprived of mental sense" is from 1520s; meaning "lacking or deprived of moral sense, unfeeling" is from 1550s. Insensate means "not capable of feeling sensation," often "inanimate;" insensible means "lacking the power to feel with the senses," hence, often, "unconscious;" insensitive means "having little or no reaction to what is perceived by one's senses," often "tactless." Related: Insensately; insensateness.

insensibility (n.)
late 14c., "absence of physical sensation, numbness," from Late Latin insensibilitas, from insensibilis "that cannot be felt" (see insensible). Meaning "quality of being imperceptible" is from 1630s. Meaning "absence of moral feeling, indifference" is from 1690s.
insensibly (adv.)
"so as not to be felt or perceived," early 15c.; see insensible + -ly (2).