Wiktionary

1. score off(Verb)

   To defeat ( in an argument), get the better of, achieve a success over, gain an advantage or win points over, make a point to the detriment or at the expense of, make appear foolish.

2. score off(Verb)

   To delete or remove (especially from a list); to score out, strike out or strike off, cross out or cross off; to draw a line through.

3. score off(Verb)

   To score from.

Origin: From score#Etymology + off#Etymology.