be whistling in the dark

be whistling in the dark

to be confident that something good will happen when it is not at all likely She seems pretty sure she'll win the title, but she may just be whistling in the dark.
See also: dark, whistle
References in periodicals archive ?
Like they know they could be whistling in the dark, but that such whistling is the only response they've got, and that they are not going to give up or let us sit there without so much as an accompanying tune.