Collins Chinese Dictionary Plus (3rd edition), 2011:
unsuccessful [ʌnsəkˈsɛsful]
adj
1
[+ attempt, application] 失败(敗)的 shībài de
2
[+ person, applicant] 不成功的 bù chénggōng de
- to be unsuccessful in or at doing sth
做某事没(沒)有成功 zuò mǒushì méiyǒu chénggōng
在这些条目还发现'unsuccessful'：
在英文解释里：
abortive
- attempted murder
- disastrous
- dud
- failed
- failing
- failure
- fall through
- flop
- fruitless
- go nowhere
- low achiever
- phone tag