DE-, = down, from.

(i) = down, down off, down to.

decĭdere = fall down, or off.
devĕnire = come to.

(ii) = off, away, aside.

dēcēdere = depart.
deflectere = turn aside.
deterrēre = frighten.

(iii) = completely.

depŏpŭlari = lay waste.
debellare = bring a war to an end.

(iv) = un- (negative).

despērare = despair.
deesse = be wanting.

E-, EX-, EC-, EF-, = out of.