cook up

verb

1. informal,  to concoct or invent (a story, alibi, etc)

2. to prepare (a meal), esp quickly

3. slang,  to prepare (a drug) for use by heating, as by dissolving heroin in a spoon

noun

1. (in the Caribbean) a dish consisting of mixed meats, rice, shrimps, and sometimes vegetables

Idioms and Phrases

Fabricate, concoct, as in She's always cooking up some excuse. [Colloquial; mid-1700s]