whistle in the dark

whistle in the dark  {v. phr.},  {informal}
To try to stay brave and forget your fear.
Tom said he could fight the bully with one hand, but we knew that he was just whistling in the dark.
(From the fact that people sometimes whistle when walking in a dark, scary place to keep up their courage.)
Categories: hand informal verb

'whistle in the dark' on video