idiominformalto beseriousordifficult:不是闹着玩儿的;不是轻而易举的事It's nojokedrivingonicyroads.在冰雪路面上开车不是件轻松的事。SMART Vocabulary: related words and phrasesComplicated and difficult to do
advanced
ambitious
ambitiously
another
arduous
formidable
formidably
get blood out of/from a stoneidiom
grail
gruelling
onerous
overdemanding
painstaking
picnic
problematic
tuff
ultra-sensitive
unresolved
unsolved
unwieldy
See more results ?(Definition ofbe no jokefrom theCambridge Advanced Learner's Dictionary & Thesaurus? Cambridge University Press)#https://dictionary.cambridge.org//dictionary/english/be-no-joke##