English

Noun

bad hair day ‎(plural bad hair days)

1. (literally) A day when one's hair seems unmanageable. [from 20th c.]
2. (idiomatic, by extension) A day when things seem to be unmanageable or go wrong.

   What's the matter with Fred? Oh, he's just having a bad hair day.‎

References

1. ↑ “Philip Kingsley, celebrity trichologist – obituary [print version: Philip Kingsley: Trichologist who treated Audrey Hepburn and Laurence Olivier and coined the term ‘bad hair day’, 17 September 2016, page 35]”, in The Daily Telegraph, 16 September 2016, archived from the original on 16 September 2016.