(a) With depreciative or privitive force: declinen, decresen, decrien, defamen, defectif, degraden, despeiren, desperat, desolat, etc.; (b) in words which as a whole denote something disagreeable or reprehensible: deceit, deceiven, decepcioun, defaut, defrauden, despisen, despit, destroien, destruccioun; (c) hence also some ME formations with pejorative or intensive dē̆-: debreiden, debresten, defaden, defilen.

Without any assignable meaning, since the simplex is not current in ME: debat, deciden, declaren, decre, defien, delectable, delaien, delit, deliveren, descripcioun, desiderable, desir, determinen, etc.