Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb sign_up

2 senses of sign up

Sense 1
sign, contract, sign on, sign up -- (engage by written agreement; "They signed two new pitchers for the next season")
       => hire, engage, employ -- (engage or hire for work; "They hired two new secretaries in the department"; "How many people has she employed?")

Sense 2
sign up -- (join a club, an activity, etc. with the intention to join or participate, "Sign up for yoga classes")
       => join, fall in, get together -- (become part of; become a member of a group or organization; "He joined the Communist Party as a young man")