backfired

As a noun terms

is .

As a verb backfired is

(backfire).

As verbs the difference between backfires and backfired

is that backfires is third-person singular of backfire while backfired is past tense of backfire.

As a noun backfires

is plural of backfire.

As verbs the difference between backfired and backfire

is that backfired is (backfire) while backfire is (of a gun or cannon) to fire in the opposite direction, for example due to an obstruction in the barrel.

As a noun backfire is

(firefighting).