insufficient · lacking · deficiency · not enough · inadequate · not worth · cannot · should not

We need more workers.

The average man fails not because he lacks ability, but because he lacks ability to concentrate.

I haven't been getting enough sleep lately.

That place's food is great, and their prices are good, but the fly in the ointment is their terrible location.

When his food supply ran short, he had to look for a new place to live.