he'd better get back there quick and prove he's not yellow
informal:cowardlylily-liveredfaint-heartedchicken-heartedpigeon-heartedcravenspiritlessspinelesstimidtimorousfearfultremblingquakingshrinkingcoweringafraid of one's own shadowpusillanimousweakfeeblesoftchickenweak-kneedgutlessyellow-belliedwimpishwimpysissysissifiedwetcandy-assedinformal:poltroonrecreantpoor-spirited
3
(of a book or newspaper) unscrupulously sensational.
he based his judgment on headlines and yellow journalism
名词
1
yellow color or pigment.
the craft detonated in a blaze of red and yellow
2
any of a number of plant diseases in which the leaves turn yellow, typically caused by viruses and transmitted by insects.