whistle in the dark
US /ˈhwɪs.əl ɪn ðə dɑːrk/
UK /ˈhwɪs.əl ɪn ðə dɑːrk/
1.
to try to make yourself feel more confident or less afraid by pretending to be brave or cheerful
:
•
He was just whistling in the dark, trying to convince himself that everything would be fine.
•
Despite his brave words, I could tell he was just whistling in the dark about the company's future.