nonchalant

Nonchalant is a synonym of heedless.

As adjectives the difference between nonchalant and heedless

is that nonchalant is casually calm and relaxed while heedless is unaware, without noticing.

As adjectives the difference between phlegmatic and nonchalant

is that phlegmatic is not easily excited to action or passion; calm; sluggish while nonchalant is casually calm and relaxed.

As a noun phlegmatic

is one who has a phlegmatic disposition.

As adjectives the difference between nonchalant and uninterested

is that nonchalant is casually calm and relaxed while uninterested is unmotivated by personal interest; unbiased, disinterested.

As adjectives the difference between impassive and nonchalant

is that impassive is having, or revealing, no emotion while nonchalant is casually calm and relaxed.

Nonchalant is a synonym of unmoved.

As adjectives the difference between nonchalant and unmoved

is that nonchalant is casually calm and relaxed while unmoved is not physically moved.

Offhanded is a synonym of nonchalant.

As adjectives the difference between offhanded and nonchalant

is that offhanded is in a casual or curt style, without preparation or thought while nonchalant is casually calm and relaxed.

As adjectives the difference between insensitive and nonchalant

is that insensitive is not expressing normal physical feeling while nonchalant is casually calm and relaxed.

Imperturbable is a related term of nonchalant.

As adjectives the difference between imperturbable and nonchalant

is that imperturbable is not easily perturbed, upset or excited while nonchalant is casually calm and relaxed.

As adjectives the difference between reserved and nonchalant

is that reserved is slow to reveal emotion or opinions while nonchalant is casually calm and relaxed.

As a verb reserved

is past tense of reserve.