Insaner

4 clues
More mad
More nutty
More cracked
More out of one's gourd
Similar answers:
Aains
Abstains
Acareerinruins
Achesandpains
Achesapains
Achirpinginsect
Acreaturewithfins
Acresandpains
Actagainstants
Actins
Addins
Addinsulttoinjury
Addledbrains
Adins
Adjoins
Adkins
Admins
Adropinsnails
Afrikaner
Againsam