responsible
Thesaurus: synonyms, antonyms, and examples not taking or showing enough care and attention
carelessThat was careless of you.
sloppySpelling mistakes always look sloppy in a formal letter.
slapdashHis work is always hurried and slapdash.
rashThat was a rash decision - you didn't think about the costs involved.
thoughtlessThe Prime Minister made a thoughtless remark about the environment.
SMART Vocabulary: related words and phrases Inconsiderate
cavalier
cavalierly
clumsily
clumsiness
cowboy
inconsiderateness
indiscreet
indiscreetly
indiscretion
indiscriminate
queue-jumper
tactless
tactlessly
tactlessness
thoughtless
ungallant
ungallantly
untactful
unthinkingly
wanton
Related words
irresponsibly
irresponsibility
irresponsible | American Dictionary
irresponsible
adjective
us/ˌɪr·ɪˈspɑn·sə·bəl/
not thinking carefully enough or not caring about what might result from actions taken:
[ + to infinitive ]It would have been irresponsible to let Claire drive home when she was so tired.
irresponsibly
adverbus/ˌɪr·ɪˈspɑn·sə·bli/