fit

The degree to which something fits.

"Since he put on weight, his jeans have been a tight fit."

Conformity of elements one to another.

"It's hard to get a good fit using second-hand parts."

The part of an object upon which anything fits tightly.

To be suitable for.

"It fits the purpose."

To conform to in size and shape.

"If I lose a few kilos, the gorgeous wedding dress might fit me."

To be of the right size and shape

"I wanted to borrow my little sister's jeans, but they didn't fit."

Suitable, proper.

"You have nothing to say about it. I'll do exactly as I see fit."

Adapted to a purpose or environment.

"survival of the fittest"

In good shape; physically well.

"You don't have to be a good climber for Kilimanjaro, but you do have to be fit."