v.1. To recite numbers in turn, as when dividing people or things into groups: The 24 children counted off by twos, forming a dozen pairs.
2. To count to an agreed upon number so that some group begins an activity at the same time: The conductor counted the band off, and they began to play. The director counted off the choir, and they began to sing. The conductor counted off, and the band began to play.
3. To decrease the score or evaluation of someone by some amount: The professor will count you off five points if you skip a class.
4. To deduct some amount from a score or evaluation: The teacher counted off one point for each mistake. The Olympic judges counted a tenth of a point off for the gymnast's wobbly landing. The teacher counts off for misspelled words.