Antonyms of adj nonchalant

1 sense of nonchalant

Sense 1
casual, insouciant, nonchalant -- (marked by blithe unconcern; "an ability to interest casual students"; "showed a casual disregard for cold weather"; "an utterly insouciant financial policy"; "an elegantly insouciant manner"; "drove his car with nonchalant abandon"; "was polite in a teasing nonchalant manner")

INDIRECT (VIA unconcerned) -> concerned -- (feeling or showing worry or solicitude; "concerned parents of youthful offenders"; "was concerned about the future"; "we feel concerned about accomplishing the task at hand"; "greatly concerned not to disappoint a small child")

Similarity of adj nonchalant

1 sense of nonchalant

Sense 1
casual, insouciant, nonchalant -- (marked by blithe unconcern; "an ability to interest casual students"; "showed a casual disregard for cold weather"; "an utterly insouciant financial policy"; "an elegantly insouciant manner"; "drove his car with nonchalant abandon"; "was polite in a teasing nonchalant manner")
       => unconcerned (vs. concerned) -- (lacking in interest or care or feeling; "the average American...is unconcerned that his or her plight is the result of a complex of personal and economic and governmental actions...beyond the normal citizen's comprehension and control"; "blithely unconcerned about his friend's plight")