not complete; lacking some part.

Football . (of a forward pass) not completed; not caught by a receiver.

Engineering . noting a truss the panel points of which are not entirely connected so as to form a system of triangles. Compare complete ( def. 8 ) , redundant ( def. 5c ) .

Logic, Philosophy .

(of an expression or symbol) meaningful only in a specific context.

(of a set of axioms) such that there is at least one true proposition (able to be formulated in terms of the basic ideas of a given system) that is not deducible from the set. Compare complete ( def. 7 ) .

Education . a temporary grade indicating that a student has not fulfilled one or more of the essential requirements for a course

If I don't hand in my term paper for last semester's English course, the professor is going to change my incomplete to an F.