as if

1. conjunction

a) as though; in a manner suggesting

The old man stumbled, as if he were about to fall.

b) in mimicry of

When the teachers back was turned, the class clown would hold his stomach as if he were ill.

2. interjection

referring to something that the speaker deems highly unlikely

“Better wait, hadnt you, Laura,” said Aunt Wess’, “and see. Maybe hell come up and speak to us.” “Oh, as if!” contradicted Laura.