make sth up
phr. v..phr. v.. to invent a story, an excuse, or information that is not true.
phr. v.. to fabricate or invent information, often for the purpose of deception or entertainment; transitive and optionally separable.
I had to make up an excuse for being late.
The children love to make up stories about dragons and magic before they go to sleep.
When questioned by the police regarding his whereabouts, the suspect attempted to make up a complex alibi involving several fictional witnesses.
the object can be a noun like 'story', 'excuse', 'lie', or 'reason'.
distinguish this sense of 'invent' from other senses of 'make up' such as 'reconcile after an argument' or 'apply cosmetics'.
He made up it.He made it up.when the object is a pronoun like 'it', it must go between the verb and the particle.