Answer: necessity

AnswerCrossword Clue
NECESSITY

Sine qua non

NECESSITY

It's indispensable

NECESSITY

It might be bare

NECESSITY
Urgent need.
NECESSITY
Penna. fort of 1754 attack
NECESSITYThe mother of invention
NECESSITYRequirement
NECESSITYInvention s mother
NECESSITYYou can't do without it