concoct

(verb) make a concoction (of) by mixing.

(verb) prepare or cook by mixing ingredients. Synonyms: cook up. Example: "Concoct a strange mixture."

(verb) invent. Synonyms: trump up. Example: "Trump up charges."

(verb) devise or invent. Synonyms: think up, think of, dream up, hatch. Examples: "He thought up a plan to get rich quickly." "No-one had ever thought of such a clever piece of software."