Sibling tense after dealing with weather (6)
I believe the answer is:
resist
'weather' is the definition.
(thesaurus)
'sibling tense after dealing with' is the wordplay.
'sibling' becomes 'sis' (short for sister).
'tense' becomes 't' (abbreviation used in many dictionaries).
'after' is a charade indicator (letters next to each other).
'dealing with' becomes 're' (regarding).
'sis'+'t'='sist'
'sist' put after 're' is 'RESIST'.
(Other definitions for resist that I've seen before include "Sister (anag)" , "Withstand a force" , "Go against" , "turn down" , "Hold out for sister" .)