"Go ahead" is a phrase used to give permission or approval to someone. It has different synonyms to convey the same meaning. For instance, you can use "proceed," which means to move forward and continue with a task or activity. Another synonym is "carry on," which means to continue doing something. "Proceed with" is also another alternative for "go ahead," and it means to take action with an intention to fulfill a task or responsibility. In some contexts, "give the green light" may be used instead of "go ahead," and it means to show approval or acceptance of a proposal or idea. Other synonyms may include "allow," "authorize," "endorse," and "sanction".