The field manager forced an unnatural laugh.

So that was Lord Feverstone-that man with the loud, unnatural laugh and the mouth like a shark.

She gave a loud, unnatural laugh.

She laughed a shrill, unnatural laugh.

She laughed a high, unnatural laugh.

Wardour burst into a hard, joyless, unnatural laugh.

She gave an exceedingly unnatural laugh.

She uttered a high-pitched unnatural laugh and ran out of the room.

He laughed, a bitter, harsh, unnatural laugh.

An unnatural laugh, but clear and with a nice tinkle to it.