ob- o- oc- of- op- in the way, = against, or out ob-ject o-mit oc-cur of-fend op-pose to throw against. to leave out. to run against; hence, to happen. to strike against. to put one's self against.
per- pel- = through, thoroughly per-vade; per-fect pel-lucid to pass through; thoroughly made. thoroughly clear.

NOTE.—Standing alone, per- signifies by: as, per annum, by the year.

post- = after, behind post-script written after.
pre- = before pre-cede to go before.
preter- = beyond preter-natural beyond nature.
pro for, = forth, or forward pro-noun pro-pose for a noun. to put forth.

NOTE.—In a few instances pro- is changed into pur-, as purpose; into por-, as portray; and into pol-, as pollute.

re- red- = back or anew re-pel red-eem to drive back. to buy back.
retro- = backwards retro-grade going backwards.
se- = aside, apart se-cede to go apart.
sine- = without sine-cure without care.
sub- suc- suf- sug- sum- sup- sus- = under or after sub-scribe suc-ceed suf-fer sug-gest sum-mon sup-port sus-tain to write under. to follow after. to undergo. to bring to mind from under. to hint from under. to bear by being under. to under-hold.

NOTE.—The euphonic variations suc-, suf-, sug-, sum-, sup-, result from assimilating the b of sub- to the initial letter of the root. In "sustain" sus- is a contraction of subs- for sub-.

subter- = under or beneath subter-fuge a flying under.
super- = above or over super-natural super-vise above nature. to over-see.

NOTE.—In derivatives through the French, super- takes the form sur-, as sur-vey, to look over.

trans- tra- through, = over, or beyond trans-gress tra-verse to step beyond. to pass over.
ultra- = beyond, or extremely ultra-montane ultra-conservative beyond the mountain (the Alps). extremely conservative.