Definitions for im-
Random House Webster's College Dictionary
Category: Usage Note
imbrute; immigrate; impassion.
Ref: var. of in-2 4 2 before b, m, p:
imbalance; immoral; imperishable.
Ref: var. of in-3 4 3 before b, m, p:
imbed; immure; impose.
Ref: var. of in-1 4 1 before b, m, p:
a form of the prefix in- not, and in- in. See In-. Im- also occurs in composition with some words not of Latin origin; as, imbank, imbitter