Answer: killer

AnswerCrossword Clue
KILLER

Very demanding

KILLER

Assassin

KILLER

Difficult challenge, in slang

KILLER
Bear of a test
KILLER
Word with giant or pain
KILLER"Totally awesome!"
KILLERRapacious whale.
KILLERGeraldine's boyfriend in Flip Wilson shows
KILLERWord with app or bee
KILLERWrestling legend Kowalski
KILLER.... whale
KILLER... whale