Busy having illustrations for magazine run off (2,4)
I believe the answer is:
at work
'busy' is the definition.
(similar in meaning)
'illustrations for magazine run off' is the wordplay.
'illustrations for magazine' becomes 'artwork' (artwork in a magazine).
'run' becomes 'r' (cricket abbreviation).
'off' is a deletion indicator.
'artwork' with 'r' removed is 'AT WORK'.
'having' acts as a link.
(Other definitions for at work that I've seen before include "busy" , "Active" , "Engaged in one's duties" .)