黑不溜秋

dark and swarthy

no; not so / (bound form) not; un-

abbr. for Heilongjiang province 黑龍江|黑龙江[Hei1 long2 jiang1]

black / dark / sinister / secret / shady / illegal / to hide (sth) away / to vilify / (loanword) to hack (computing)

to slip away / to escape in stealth / to skate

used in 冰溜[bing1 liu4]

autumn / fall / harvest time

old variant of 秋[qiu1]

see 鞦韆|秋千[qiu1 qian1]