ETYM AS. blîthe blithe, kind; akin to Goth. bleiths kind, Icel. blîthr mild, gentle, Dan. and Swed. blid gentle, Dutch blijd blithe, Old High Germ. blîdi kind, blithe.
1. Carefree and happy and lighthearted; SYN. blithesome, lighthearted, lightsome.
2. Lacking or showing a lack of due concern.

1. Cheerfully irresponsible; SYN. devil-may-care, freewheeling, happy-go-lucky, harum-scarum, slaphappy.
2. Free of trouble and worry and care; SYN. unworried.

ETYM as. cearleás.
1. Effortless and unstudied.
2. Marked by lack of attention or consideration or forethought or thoroughness; not careful.
3. Showing an unthinking lack of consideration.
4. (Usually followed by 'of') Without due thought or consideration; SYN. thoughtless, regardless.

ETYM Old Eng. debonere, Old Fren. de bon aire, debonaire, of good descent or lineage, excellent, debonair, French débonnaire debonair; de of (Latin de) + bon good (Latin bonus) + aire. Related to Air, and Bounty, Bonair.
Having a sophisticated charm; SYN. debonaire, debonnaire, suave.

Stylish, charming, dashing

1. Free and relaxed in manner
2. Showing lack of emotional involvement; SYN. detached, uninvolved.
At rest; untroubled; at ease.
(French) (fem. -ée) “disengaged”; at ease; unworried.

Blithely unconcerned; carefree

1. Characterized by careless unconcerned; SYN. reckless.
2. Marked by or paying little heed or attention

ETYM French.
Careless; heedless; indifferent; unconcerned.
Lighthearted and unconcerned.

1. Ffree from care, anxiety, or seriousness; happy-go-lucky
2. Cheerfully optimistic and hopeful; easygoing

ETYM Old Eng. listles, lustles. Related to Lust.
Lacking zest or vivacity.

Leaving vulnerable; SYN. neglectful of.
Given to neglecting; careless, heedless

ETYM French négligent, Latin negligens,p. pr. of negligere. Related to Neglect.
1. Characterized by neglect and undue lack of concern.
2. Marked by insufficient care or attention.

ETYM French, from non not (Latin non) + chaloir to concern one's self for, from Latin calere to be warm, to be inflamed with desire, to be troubled. Related to Non-, and Caldron.
Indifferent; careless; cool.
Having an air of easy unconcern or indifference.

ETYM Latin serenus to grow dry.
1. Calm and peaceful.
2. Completely clear and fine.

Not embarrassed SYN. unembarrassed.

1. Easy in mind; not worried
2. Lacking in interest or care or feeling.
3. Not occupied or engaged with

1. Free from turmoil or worries
2. Not beset by troubles or disturbance or distress

Used interjectionally to express a lack of concern about consequences or risks

ETYM From Chat, by way of reduplication.
Light informal conversation for social occasions; SYN. small talk, gab, gabfest, gossip, tittle-tattle, chin-wag, chin-wagging, causerie. chit-chat.