1) Aloof 2) Apathetic 3) Blithe 4) Carefree 5) Careless 6) Casual 7) Detached 8) Fearless 9) Indifferent 10) Insouciant 11) Nonchalant 12) Relaxed 13) Uncaring 14) Uninvolved 15) Untroubled 1) Blase 2) Blithe 3) Careless 4) Casual 5) Degage 6) Detached 7) Disinterested 8) Easy in mind 9) Indifferent 10) Insouciant 11) Nonchalant 12) Not caring 13) Not involved or interested 14) Not occupied or engaged with 15) Not worried 16) Uninvolved 17) Untroubled 18) Unworried 
• (a.) Not concerned; not anxious or solicitous; easy in mind; carelessly secure; indifferent; as, to be unconcerned at what has happened; to be unconcerned about the future.
[adj] - easy in mind 2. [adj] - not occupied or engaged with 3. [adj] - lacking in interest or care or feeling
adjective not occupied or engaged with; `readers unconcerned with style`
not involved or interested; disinterested. · not caring; unworried; free from solicitude or anxiety.