Have a yellow streak down one’s back informal verb phrase
Used to describe someone that is cowardly.
She never dares to be alone at home. She obviously has a yellow streak down her back.
You shouldn’t participate in our plan if you have a yellow streak down your back.
He chose to remain silent about their wrongdoing. He has a yellow streak down his back.
To shake a lot due to the cold or fear
Being so scared, confused, and astonished that you can't think or do anything.
Very fearful.
1. Someone who is unsociable or who stops other people from enjoying themselves.
2. A weed.
The verb "have" should be conjugated according to its tense.
The origin of this idiom may be traced back to European culture, where the color yellow is associated with cowardice.