Letters that make sign up
s, g, n, p, i, u are letters that make 'sign up'
2 possible definitions for 'sign up'
Under this definition, sign up is a verb and has the following properties:
'sign up' can be a type of join, get together, fall in.
enlist is a type of sign up.
Under this definition, sign up is a verb and has the following properties:
contract out is a type of sign up.