2.VerbAs go + at it; spoken emphasis typically on 'at'.
To engage in some activity, especially vigorously or enthusiastically."We were all going at it like crazy, trying to get the job finished before the deadline.; Joe accidentally spilled his drink on Eric, Eric got up and insulted his mother, and before you know it, they were going at it.; I walked into my dorm room and caught my roommate and his girlfriend going at it."
4.VerbTo fight or argue."Joe accidentally spilled his drink on Eric, Eric got up and insulted his mother, and before you know it, they were going at it."