faint-hearted

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++faint-heart·ed /ˌfeɪnt ˈhɑːtɪd $ -ɑːr-/ adjective  1  WORK HARDnot trying very hard, because you do not want to do something, or you are not confident that you can succeed 〔因不想做或没有信心而〕半心半意的，未尽全力的 SYN half-hearted She made a rather faint-hearted attempt to stop him from leaving. 她没有尽力挽留他。2. something is not for the faint-hearted DIFFICULTused humorously to say that something is difficult and needs a lot of effort 某事不是弱者所能干的〔幽默用法〕

Examples from the Corpus

faint-hearted• If predators do not oblige, the pests are picked off and squashed - not a job for the faint-hearted!• None of this is for the faint-hearted.• Not a city for the lily-livered or faint-hearted.• Playing foreign markets is not for the faint-hearted.• The coastguard duties included patrolling paths at the top of high and sheer cliffs - not a job for the faint-hearted.• This is not an investment for the faint-hearted.• Neither Baron Korf nor Iakov Rostovtsev owned serfs, but the one was faint-hearted and the other unimaginative.• Not that it is a post for the faint-hearted, even today.

faint-heart·ed adjectiveChineseSyllable  

not because do trying Corpus hard, very not you

faint-hearted
faint-heart‧ed /ˌfeɪnt ˈhɑːtəd $ -ɑːr-/ adjective
1. not trying very hard, because you do not want to do something, or you are not confident that you can succeed
   SYN  half-hearted:
    She made a rather faint-hearted attempt to stop him from leaving.
2. something is not for the faint-hearted used humorously to say that something is difficult and needs a lot of effort