A group of words which have a different meaning when used together from the one they would have if you took the meaning of each word separately.
sketch something out
to create a rough idea or image of something by sketching or some other means. (Does not necessarily require an actual sketch.)
Sally sketched the furniture arrangement out so we could get an idea of what it was to look like.
A phrase that combines a verb with a preposition or adverb or both and that functions as a verb whose meaning is different from the combined meanings of the individual words.
A compilation of 50 phrasal verbs.