<*logic*>
an operator in a logical language (sentence, logic) is said
to be truth functional iff the truth value of a
proposition in which it appears is wholly determined by the
truth value of the subsiduary propositions on which it operates.
E.g. the truth value of p&q is wholly determined once we know the
truth value of p and the truth value of q; hence the
operator, &, is truth functional. non-truth-functional
conjunction, dagger function, disjunction,
equivalence, implication, negation, stroke function

Try this search on OneLook / Google