1. Godan verb with 'mu' ending, Transitive verb

   to swallow; to gulp down

   洪水がその村を飲み込んでしまった。

2. to understand; to grasp; to take in; to catch on; to learn

3. to engulf; to swallow up

4. to be filled with (people); to contain

5. to swallow (one's words); to suppress (a yawn, tears, etc.); to stifle; to hold back

Also written 呑み込む【のみこむ】nomikomu