Unimportant test with India against joining in (7)
I believe the answer is:
trivial
'unimportant' is the definition.
(similar in meaning)
'test with india against joining in' is the wordplay.
'test' becomes 'trial' (synonyms).
'with' means one lot of letters goes inside another.
'india' becomes 'i' (phonetic alphabet: alpha, bravo, charlie etc.).
'against' becomes 'v' (abbreviation for 'versus').
'joining in' is an insertion indicator.
'trial' going around 'i' is 'triial'.
'triial' enclosing 'v' is 'TRIVIAL'.
(Other definitions for trivial that I've seen before include "Of little value" , "Footling" , "Petty, piffling" , "not significant" , "Unimportant, minor" .)