I wasna fou, but just had plenty.

In Scots, “I wasna fou” means “I wasn’t drunk,” while “just had plenty” suggests having had a great deal to drink (or more broadly, having had one’s fill). The line plays on the common social excuse that tries to preserve dignity while admitting excess: the speaker denies the stigmatized label (“drunk”) but concedes the behavior that would lead others to apply it. In Burns’s world of taverns, conviviality, and sharp-eyed moral observation, such phrasing captures both humor and self-deception—how people negotiate reputation, pleasure, and propriety through language. The wit lies in the hair-splitting distinction between being “fou” and having “plenty.”