Crossword Genius

Sack fellow first responder (7)

Ross

I believe the answer is:

fireman

I'm a little stuck... Click here to teach me more about this clue!

'first responder' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?

'sack fellow' is the wordplay.
'sack' becomes 'fire' (both can mean to dismiss from a job).
'fellow' becomes 'man' (fellow can mean a man).
'fire'+'man'='FIREMAN'

Can you help me to learn more?

(Other definitions for fireman that I've seen before include "Railway driver's assistant" , "who does a rushed job on tender?" , "Conflagration fighter" , "he puts out at work" , "Red engine driver" .)

I've seen this clue in The Mirror.
Want a hint initially instead of a full solution? Install my app