It was no place to be casual about a stranger.

Yeah, that's right: She was trying so hard to be casual about it.

I eased toward the door, trying to be casual about it.

She'd been hoping against hope this morning that he wouldn't be casual about last night.

I'm not someone who's casual about that kind of language.

I think we are being much too casual about this matter.

She was going to try and be casual about it.

Thinking he was rather casual about his trade as a fisherman, she turned to him.

Was she just pretending to be so casual about it?

No one seeing me for the first time can act casual about it.