After union, struggle and die without assistance (7)
I believe the answer is:
unaided
'without assistance' is the definition.
(I've seen this before)
'after union struggle and die' is the wordplay.
'after' means one lot of letters go next to another.
'union' becomes 'u' (common abbreviation as in Trades Union Congress).
'struggle' indicates anagramming the letters (I've seen 'struggling' mean this (I've seen this in other clues)).
'and'+'die'='anddie'
'anddie' anagrammed gives 'naided'.
'u' put next to 'naided' is 'UNAIDED'.
(Other definitions for unaided that I've seen before include "Without help or support" , "having received zero help" , "Quite without assistance" , "Without extra help" , "Done by oneself alone" .)