Ad lib and Make up

Ad lib adverb - Without advance preparation.

Make up and ad lib are semantically related. in conceive topic. In some cases you can use "Make up" instead a verb phrase "Ad lib", when it comes to topics like formulate, create, improvise, improvise speech.

Make up verb - To be all the substance of.

Ad lib and make up are semantically related. Sometimes you can use "Ad lib" instead a verb "Make up".