Google warns that when you delete your Gmail, you will no longer be able to send or receive email at that address, though it may be possible to recover the Gmail account if you change your mind and no one else will be able to use the account in the future.
Finally, if you want to delete your Google account, here’s how. deleting the Gmail account won't delete your Google account.
7. Enter an existing email address you want to sign in to Google services with and click “Send verification email.” You cannot use another Gmail address.