rear one's head

rear one's head (third-person singular simple present rears one's head, present participle rearing one's head, simple past and past participle reared one's head)

1. To raise one's head.
2. (idiomatic, of something unpleasant or unwelcome) To appear and cause problems or stress, especially at an inopportune time.
   • 2021 October 6, Greg Morse, “A need for speed and the drive for 125”, in RAIL, number 941, page 53:

     One problem that reared its head in 1983 would prove more difficult to solve, with the heat that summer leading to a number of engine failures.

• Often used with ugly: rear its ugly head.

• “rear one's head”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.
• “rear its ugly head” in Longman Dictionary of Contemporary English, Longman.
• “rear its ugly head” in the Cambridge English Dictionary, Cambridge: Cambridge University Press.