Sign up - Crossword Clue, Answer and Explanation

'sign up' is the definition.
(I've seen this in another clue)

This is all the clue.

(Other definitions for enter that I've seen before include "Make a record of" , "Treen (anag.)" , "Enlist, join up" , "Record (in a log)" , "Register (as a competitor)" .)

I've seen this clue in the Penny Press, The Telegraph, The Guardian, The Independent and The Mirror.

'sign up' is the definition.
(I've seen this before)

This is the entire clue.

(Other definitions for enrol that I've seen before include "Join as member" , "register for classes" , "Sign on, register" , "Join up, sign on" , "Bring into service" .)

I've seen this clue in the Penny Press, The Telegraph, The Guardian, The Independent and The Mirror.

'sign up' is the definition.
(enlisting is a kind of signing up)

This is all the clue.

(Other definitions for enlist that I've seen before include "Join up - tinsel (anag)" , "Enrol in armed forces" , "Take the Queen's shilling" , "Join up, sign on" , "Draft" .)

I've seen this clue in the Penny Press, the USA Today, The Telegraph, the King Feature Syndicate, The Guardian, The New York Times, The Independent, the Universal, the LA Times, The Star Tribune, the Sydney Morning Herald, the Newsday, The Mirror and The Sun.

'sign up' is the definition.
(I've seen this in another clue)

This is all the clue.

(Other definitions for recruit that I've seen before include "Newly enlisted person" , "He's just joined up, often the armed forces" , "New member of army etc" , "Trainee" , "Take on" .)

I've seen this clue in The Sunday Times.

Sign up (6)