Definitions:
of the colour between green and orange in the spectrum, a primary subtractive colour complementary to blue; coloured like ripe lemons or egg yolks

not brave; cowardly

(of a style of writing, especially in journalism) lurid and sensational

yellow colour or pigment

a yellow ball or piece in a game or sport, especially the yellow ball in snooker

used in names of moths or butterflies that are mainly yellow in colour.

any of a number of plant diseases in which the leaves turn yellow, typically caused by viruses and transmitted by insects.

become yellow, especially with age