sit up and take notice

sit up and take notice (third-person singular simple present sits up and takes notice, present participle sitting up and taking notice, simple past sat up and took notice, past participle sat up and taken notice)

1. To start to pay attention suddenly.

• prick up one's ears

• “sit up and take notice” in the Cambridge English Dictionary, Cambridge: Cambridge University Press.
• “sit up and take notice” (US) / “sit up and take notice” (UK) in Macmillan English Dictionary.
• “sit up and take notice”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.