1. de- a prefix, occurring orig. in loanwords from Latin, used to form verbs that denote motion or conveyance down from, away, or off (deflect; descend); reversal or undoing of the effects of an action (deflate); extraction or removal of a thing (decaffeinate); thoroughness or completeness of an action (despoil).
Etymology: (ME < L dē-, prefixal use of dē (prep.) from, away from, of, out of; in some words, < F < L dē- or dis-dis -1)
Definition of 'de-'
Webster Dictionary
1. de- a prefix from Latin de down, from, away; as in debark, decline, decease, deduct, decamp. In words from the French it is equivalent to Latin dis-apart, away; or sometimes to de. Cf. Dis-. It is negative and opposite in derange, deform, destroy, etc. It is intensive in deprave, despoil, declare, desolate, etc
Definitions of de- 
