to chicken out
2fevereiro 23, 2010 por fabiobossard
to chicken out – amarelar
When you are supposed to do something and you change your mind because you are afraid to do it, you chicken out. The word is related to “chicken”. That’s why in movies when someone chickens out, the others will immitate a chicken.
Jack was going to bungee jump on his birthday, but he chickened out the last minute.
English this way! 
We also make the sound of a chicken, but I’m not sure if that’s what you meant by “immitate a chicken”…cause we also might fold our hands under our armpits and flap them like wings, lol.
In the old days, saying someone was ‘yellow’ meant he/she was a chicken. Also, to play chicken is to challenge something that could potentially hurt you.
Ex., “I played chicken with the cars” means you stood in the road and waited until the oncoming cars came really close to hitting you until you moved out of the way. Sort of the “let’s see who moves first” idea.
Cheers
Yes, I meant the sound and/or the gestures.