Denshi Jisho — Online Japanese dictionary

駄目 だめ 1: (Usually written using kana alone) no good; not serving its purpose; useless; broken;
2: (Usually written using kana alone) hopeless; wasted; in vain; purposeless;
3: (Usually written using kana alone) cannot; must not; not allowed
Common word, Na-adjective, Noun 
駄目元 だめもと giving something a try because one has nothing to lose
Noun, Slang 
駄目押し だめおし 1: making doubly sure;
2: insurance runs (baseball)
Expression 
駄目出し だめだし judging someone (negatively) and urging them to improve; finding fault (in somebody's work)
Noun, Slang 
駄目になる だめになる to spoil; to break; to go bad; to go wrong; to fail
Expression, Godan verb with ru ending 
駄目を押す だめをおす to make sure; to make doubly sure
Expression, Godan verb with su ending 
駄目人間 だめにんげん useless member of society; hopeless case; failure
Noun 
駄目で元々 だめでもともと giving something a try because one has nothing to lose
Expression 

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