英语词源字典 - 在线词源网站

exterminate (v.)[exterminate 词源字典]: 1540s, "drive away," from Latin exterminatus, past participle of exterminare "drive out, expel, put aside, drive beyond boundaries," also, in Late Latin "destroy," from phrase ex termine "beyond the boundary," from ex- "out of" (see ex-) + termine, ablative of termen "boundary, limit, end" (see terminus).

Meaning "destroy utterly" is from 1640s in English, a sense found in equivalent words in French and in the Vulgate; earlier in this sense was extermine (mid-15c.). Related: Exterminated; exterminating.[exterminate etymology, exterminate origin, 英语词源]
lesser (adj.): early 13c., a double comparative, from less + -er (2). Johnson calls it "a barbarous corruption of less, formed by the vulgar from the habit of terminating comparatives in -er." As an adverb from 1590s; now generally poetic or obsolete except in expression lesser-known (1813).
terminate (v.): early 15c., "bring to an end," from Latin terminatus, past participle of terminare "to limit, set bounds, end" (see terminus). Intransitive sense of "to come to an end" is recorded from 1640s; meaning "dismiss from a job" is recorded from 1973; that of "to assassinate" is from 1975. Related: Terminated; terminating.