The term is correct. Grammatically, we would say, "I love vacuous truths", or, "I love vacuously true statements". (To my ear the second version sounds very sli

The term is correct. Grammatically, we would say, "I love vacuous truths", or, "I love vacuously true statements". (To my ear the second version sounds very slightly more appropriate, because in mathematics "vacuously true" is a bit of a set phrase, but both are fine.)