(1):

(n.) An offense which occasions a total forfeiture either lands or goods, or both, at the common law, and to which capital or other punishment may be added, according to the degree of guilt.

(2):

(n.) An act on the part of the vassal which cost him his fee by forfeiture.

(3):

(n.) A heinous crime; especially, a crime punishable by death or imprisonment.