Screwy and for grins are semantically related. in amusing topic. In some cases you can use "Screwy" instead an adjective phrase "For grins", when it comes to topics like ridiculous.
Screwy adjective – Different from the ordinary in a way that causes curiosity or suspicion. For grins and screwy are semantically related. Sometimes you can use "For grins" instead an adjective "Screwy". Nearby Words: screw, screwed, screwing