词源：

　　前缀ob-来源于拉丁介副词ob，原意是“toward"，在构词当中又引申出“against,inversely”等意思，还有“to, in the way, over, away, completely,intensive”等含义。ob-是个原生词缀，一般与拉丁词根缀合，所构成的派生词的词性取决于词根或后缀的属性。由于语音的同化作用，ob-在c,f,p前面，变成oc-,of-,op-。在元音字母及其它辅音字母前，ob-形态不变。

　　每个前缀的纯英语来源解释：

　　ob-

　　prefix meaning "toward, against, across, down," also used as an intensive, from Latin ob "toward, to, over against, in the way of, by reason of, about, before, in front of," from PIE root *epi, also *opi "near, against" (see epi-).

　　oc-

　　assimilated form of ob- before -c-.

　　of-

　　assimilated form of ob- before -f-.

　　op-

　　assimilated form of ob- before -p-.

　　os-

　　frequent form of ob- before -c- and -t- in words from Latin.

　　现在对这几个前缀的含义整理如下：

　　1.逆着…，和…敌对，和…相反

　　oppress, opprobrium

　　2.向着…，给…

　　obnoxious, opportune

　　3.妨碍地

　　officious, obsequious, obsession

　　4.越过，盖住

　　obscene, obfuscate, obscure

　　5.远远地，消失

　　obviate, omission

　　6.表强调[完全，干脆，厉害地，继续]

　　obese, obdurate, obeisance

　　另外，前缀ob-还有很多变形。

　　1.oc-[在辅音字母c之前]

　　occult, occupied

　　2.of-[在辅音字母f之前]

　　offensive, officiator

　　3.op- [在辅音字母p之前]

　　opponent, inopportune

　　4.os-[在辅音字母t之前]

　　ostensible, ostentatious

　　5. o- [在辅音字母m之前]

　　此外，前缀ob-还有一些同义前缀，也有“反对，抵抗”的意思,这些词缀是：anti- ,contra- ,contro-,counter-,with-。

　　1.officiate [of

　　vt. at+sth perform the duties of an office or position; preside 行使职务，行使职权;主持 oflice 事务所;政府机关 officer 军官 officiator 主婚人 offcial 正式的，公务的;公务员，官员

　　ex)A Unitarian minister officiated at his funeral.

　　一位一神论派的牧师主持了他的葬礼。

　　2.oppress [op

　　vt. keep down by unjust or cruel government; rule unjustly or cruelly; weigh heavily on 压迫，压制;用暴政统治;使烦闷，施加重压

　　oppression 压制，压抑;迫害 oppressor 压制者，暴君 oppressive 压制的,压迫的;烦闷的，窒息的

　　ex) Organized religion is often used to oppress people, in my view

　　我认为，组织化的宗教往往被用来压制人民。