A bit short when lit up (5,2)
I believe the answer is:
light on
'a bit short' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'when lit up' is the wordplay.
I cannot quite see how this works, but
'when' could be 'on' (I've seen this in other clues) and 'on' is present in the answer.
'lit' could be 'light' (similar in meaning) and 'light' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
I've seen this clue in the Sydney Morning Herald.
Want a hint initially instead of a full solution?
Install my app