Getting awfully glum about a row over bait

'over bait' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.

'getting awfully glum about a row' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'row' is 'wor' which is present in the answer.
an anagram of 'glum' is 'lugm' which is located in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?