The phrasal verb "finish off" is primarily used in informal speech, though it can occasionally appear in more formal contexts when the tone permits. Its general usage patterns include talking about completing a task or the last part of an activity, often implying a sense of finality or thoroughness. Additionally, it can mean to consume the last portion of something, such as food or drink. "Finish off" might also be used metaphorically, for example, to indicate defeating an opponent conclusively. The versatility of "finish off" in different contexts makes it a common choice for conversational English, though it's less frequent in formal writing unless the context is suitable or casual language is appropriate.
B1
PreIntermediate
1. To complete or conclude something, often in a decisive manner.
I need to finish off this term paper before I go to bed.
She finished off the report by including a summary of all her major findings.
2. To eat or use up completely.
There was only a small piece of cake left, so I decided to finish it off.
We finished off the last of the pizza during the football game.
3. To kill, destroy, or defeat something or someone so that it or they are no longer a threat.
The boxer managed to finish off his opponent in the final round.
The hunter finished off the injured deer with a clean shot.