Phrasal verbs, also called two-word verbs, are idiomatic expressions wherein the second element of the verb (the adverb or particle) is not necessarily predictable.
Phrasal Verb:
patch something up
Meaning / Example:
1. to repair something in a hurry; to make something temporarily serviceable again. > Can you patch this up so I can use it again? > I'll patch up the hose for you.
2. to "repair" the damage done by an argument or disagreement. > Mr. and Mrs. Smith are trying to patch things up.
Phrasal verbs consists of a basic verb + another word or words. The two or three words that make up a phrasal verb form a short 'phrase' - which is why we call them 'phrasal verbs'.