Phrasal verbs are compound verbs that result from combining a verb with an adverb or a preposition. The resulting compound verb is idiomatic.
catch something up in something
to ensnare and capture something in something.
We caught a large number offish up in the net.
A verb combined with an adverb or a preposition, or sometimes both, to give a new meaning.
A compilation of 50 phrasal verbs.