indiscreet

Từ điển Oxford Advanced Learner 8th

in·dis·creet AW BrE [ˌɪndɪˈskriːt] NAmE [ˌɪndɪˈskriːt] adjective
not careful about what you say or do, especially when this embarrasses or offends sb
•an indiscreet comment
•It was indiscreet of him to disclose that information.
Opp: ↑discreet
Derived Word: ↑indiscreetly

Word Origin:
[indiscreet indiscreetly] late Middle English (originally as indiscrete in the sense ‘lacking judgement’): from late Latin indiscretus ‘not separate or distinguishable’ (in medieval Latin ‘careless, indiscreet’), from in- ‘not’ + discretus ‘separate’ (past participle of discernere ‘discern’, the sense arising from late Latin discretio ‘separation’, from discernere, from dis- ‘apart’ + cernere ‘to separate’).

Example Bank:
•One indiscreet comment could spoil the whole thing.