Clan's brief attempt to live on island (5)
I believe the answer is:
tribe
'clan's' is the definition.
(I know this)
'brief attempt to live on island' is the wordplay.
'brief' means to remove the last letter (a shorter or briefer version of the word).
'attempt' becomes 'try' (synonyms).
'to live' becomes 'be' ('be' can be a synonym of 'live').
'on' is a charade indicator (letters next to each other).
'island' becomes 'i'.
'try' with its last letter taken away is 'tr'.
'be' put after 'i' is 'ibe'.
'tr'+'ibe'='TRIBE'
(Other definitions for tribe that I've seen before include "Division of, eg, North American natives" , "Ethnic grouping" , "Group of common descent, culture etc" , "Group of people; big family" , "Ethnic group" .)