insouciantly

As adverbs the difference between insouciantly and carelessly

is that insouciantly is in an insouciant manner while carelessly is giving the appearance of carelessness; relaxedly.

As adverbs the difference between unconsciously and insouciantly

is that unconsciously is in a subconscious manner; something done unknowingly while insouciantly is in an insouciant manner.

As an adverb insouciantly

is in an insouciant manner.

As an adjective casual is

happening by chance.

As a noun casual is

(british|nz) a worker who is only working for a company occasionally, not as its permanent employee.

As adverbs the difference between insouciantly and casually

is that insouciantly is in an insouciant manner while casually is in a casual manner.