beat the (living) daylights out of (one)

1. To physically attack one, as with punches and other blows, such that they suffer significant injury. This phrase can be used both literally and hyperbolically. Our neighbor is in the hospital because a burglar beat the daylights out of him. I'm worried that the captain of the football team will beat the living daylights out of me if he finds out that I'm secretly seeing his girlfriend. Oh, my boyfriend knows that I would beat the living daylights out of him if he ever lies to me about something that serious.

2. To defeat one decisively in a competition. The final score was 17–1? Wow, we really beat the living daylights out of that team! As predicted, that candidate dominated in the election and beat the living daylights out of her opponent. The young team's inexperience showed on the field today, as the veteran squad beat the living daylights out of them.

beat the (living) daylights out of

give someone a very severe beating. informal

Daylight or daylights has been used from the mid 18th century as a metaphor for ‘eyes’, and here has the extended sense of any vital organ of the body.