word-forming element usually meaning "with, together," from Latin com, archaic form of classical Latin cum "together, together with, in combination," from PIE *kom- "beside, near, by, with" (compare Old English ge-, German ge-). The prefix in Latin sometimes was used as an intensive.
Before vowels and aspirates, it is reduced to co-; before -g-, it is assimilated to cog- or con-; before -l-, assimilated to col-; before -r-, assimilated to cor-; before -c-, -d-, -j-, -n-, -q-, -s-, -t-, and -v-, it is assimilated to con-, which was so frequent that it often was used as the normal form.
commit ( com 加强语气，mit 送) vt. 把 ... 送给/交托；犯罪；做错事 1402
cooperate vi. 合作、配合；协力 4053
correlate vi. 使互相关联 5338
collaborate vi. 合作；勾结、通敌 6438
concise adj. 简明的，简洁的 16558
conclude -> conclusion
decide -> decision
convert -> conversion
permit -> permission
admit -> admission
eat -> -es/-ed (obese、edible）
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."
element meaning "into, in, on, upon" (also im-, il-, ir- by assimilation of -n- with following consonant), from Latin in- "in," from PIE root *en "in."
In Old French (and hence in Middle English) this often became en-, which in English had a strong tendency to revert to Latin in-, but not always, which accounts for pairs such as enquire/inquire. There was a native form, which in West Saxon usually appeared as on- (as in Old English onliehtan "to enlighten"), and some of those verbs survived into Middle English (such as inwrite "to inscribe"), but all now seem to be extinct.
income ( in 进入，come 来 ) n. 收入，收益，所得 1141
intact ( in = not, tact = touch 触、摸 ) adj. 完整的；原封不动的；未受损伤的 4679
import (in = in 进入, port 港口、码头) n. 输入；进口；进口货 4087。 export ( ex 出)
immoral (im = not, moral 道德的) adj. 不道德的；邪恶的；淫荡的 9992
artisan (artis 技术、技艺， -an 人) n. 工匠、技工
veteran (veter = year 年) n. 老兵；老手； adj. 经验丰富的
approval n. 赞成；批准；认可
artificial (arti 技术，fic 做，-al 的) adj. 人造的；仿造的；虚伪的
circular adj. 圆形的；循环的；间接的