Engrossed while camping (6)
I believe the answer is:
intent
'engrossed' is the definition.
(synonyms)
'while camping' is the wordplay.
'while' becomes 'in' (I can't explain this - if you can you should believe this answer much more).
'camping' becomes 'tent' (I've seen this in other clues).
'in'+'tent'='INTENT'
Can you help me to learn more?
(Other definitions for intent that I've seen before include "Concentrating on a particular purpose" , "Objective" , "Committed" , "Mean to" , "set" .)