We would say

The use of the word is widespread nowadays.

and there widespread would be an adjectival modifier of the subject use attached to it by the predicate is.

Widespread is an interesting adjective. It's really a past-participle form, spread, with a sort of locative modifier wide, rolled up into a ball, as it were. If we untangle the ball we could say:

The use of the word is spread wide nowadays.

We would say

The use of the word is widespread nowadays.

and there widespread would be an adjectival modifier of the subject use attached to it by the predicate is.

Widespread is an interesting adjective. It's really a past-participle form, spread, with a sort of locative modifier wide, rolled up into a ball, as it were. If we untangle the ball we could say:

The use of the word is spread wide nowadays.

P.S. Compare parboiled, overdone.