whistle in the dark

US /ˈhwɪs.əl ɪn ðə dɑːrk/
UK /ˈhwɪs.əl ɪn ðə dɑːrk/
"whistle in the dark" picture
1.

闇の中で口笛を吹く, 虚勢を張る

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.
彼はただ闇の中で口笛を吹いて、すべてがうまくいくと自分に言い聞かせようとしていた。
Despite his brave words, I could tell he was just whistling in the dark about the company's future.
彼の勇敢な言葉にもかかわらず、会社の将来について彼はただ闇の中で口笛を吹いているだけだとわかった。