Answer:

deadly

Answer	Crossword Clue
DEADLY	Fatal
DEADLY	Not just dangerous
DEADLY	Really boring

DEADLY	Excruciatingly boring
DEADLY	Lethal
DEADLY	... nightshade
DEADLY	Extremely accurate
DEADLY	Mortal.
DEADLY	Seven ... sins.
DEADLY	Implacable.
DEADLY	Unbearable: Colloq.

DEADLY	Lethal.
DEADLY	Fatal.
DEADLY	Extremely boring
DEADLY	Like certain sins
DEADLY	Mortal
DEADLY	Testament: "First Strike Still ..."
DEADLY	Extremely poisonous
DEADLY	Totally boring