I have two gmail accounts in my outlook I have set in gmail to forward one to the other so I only need one account in outlook, but I still want to send as the account I am removing. How can I set the removed account to send as default but not receive emails? Does this make sense?

Currently, there's no such option in Outlook.

However, we may still keep the account and configure as the following steps:

SEND/RECEIVE tab -> Send/Receive Groups -> Define Send/Receive Groups -> Edit -> Choose that Gmail account -> choose include the selected account in this group check box, then uncheck Receive mail items -> Click OK.

I hope the information is helpful to you.