Crossword Genius

Draining liquid food served with fish (9)

Ross

I believe the answer is:

gruelling

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

'draining liquid' is the definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?

'food served with fish' is the wordplay.
'food' becomes 'gruel' (gruel is a kind of food).
'served with' means one lot of letters go next to another.
'fish' becomes 'ling' (ling is a kind of fish).
'gruel'+'ling'='GRUELLING'

Can you help me to learn more?

(Other definitions for gruelling that I've seen before include "Severe" , "Strenuous" , "Arduous, backbreaking" , "Demanding" .)

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