Collocations for casual - adj.

appear, be, sound

extremely, fairly, very, etc.
almost
She sounded almost casual.

apparently, seemingly
carefully
There was something a little too carefully casual in his tone.

deceptively

about
He was very casual about it all.

Casual is used with these nouns:
acquaintance, affair, attitude, basis, chat, clothes, clothing, comment, contract, conversation, cruelty, dismissal, dress, elegance, employment, encounter, fan, glance, indifference, inspection, labour, labourer, listener, look, manner, observation, observer, pants, partner, reader, reference, relationship, remark, restaurant, salute, sex, shoe, shrug, speech, stroll, style, tone, user, vacancy, viewer, visit, visitor, wave, wear, work, worker