Verb
listen up (third-person singular simple present listens up, present participle listening up, simple past and past participle listened up)
(idiomatic, informal) To listen closely; to pay attention.
I'm only gonna say this once, so you really need to listen up.
Local Entertainment — published: 5/6/2018 Listen Up: English teachers' performance will take viewers down a 'two-track road' Source: Internet
Listen Up is a Q&A featuring locals in the arts and culture community. Source: Internet