In Japanese, the う - Verb 込（こ）む ‘to jam into’ is frequently used as a 接尾語（せつびご） (suffix) to convey several different meanings. The primary meanings are as follows:
(A) 込（こ）む - To enter completely into doing (A), or the state of being in (A).
(A) 込（こ）む - To enter a state of doing (A) that will not be considered complete until ‘success’.
(A) 込（こ）む - To enter a state of doing (A) that cannot be escaped from.
In this lesson, we will exclusively focus on the second and third meanings, which are usually translated as ‘to remain in (A)’, ‘to thoroughly do (A)’, ‘to do (A) deeply’, or ‘to do (A) intensely’. This form will be attached to the 連用形（れんようけい） (conjunctive form) of other verbs.
The police went to talk to the person that remained seated in the middle of the road.
It’s already this time, we got lost in talking, didn't we?
You don't have to think so deeply about this.
I am held up working right now, so I will call you back once my hands are free.
Despite the multiple meanings, 込（こ）む can almost always be thought of as ‘jamming (B) into (A)’. This means that whatever the (A) action is, will be something that is not easily entered, but also not easily escaped from.