COMMON If someone is quick off the mark, they are quick to respond to something, or to take advantage of an opportunity. He knows what it is like to have his privacy invaded — and has been quick off the mark to do something about it. There are bargains to be had in the sales but you need to be quick off the mark. Note: You can also say that someone is first off the mark, meaning that they respond more quickly than anyone else. Thompson always seems to be the first off the mark with a new trend. Note: You can also say that someone is slow off the mark, meaning that they are slow to respond. There have been complaints that the international relief efforts on behalf of the refugees were slow off the mark. Note: The `mark' in this expression is the line which runners stand behind at the start of a race.