Totally absorbed (9)
I believe the answer is:
engrossed
'totally absorbed' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for engrossed that I've seen before include "Son's greed (anag) - totally attentive" , "Wrapt, immersed" , "'Rapt, immersed (9)'" , "Complete absorbed, rapt" , "Totally absorbed" .)