To pass up something means to refuse to take advantage of an offer or opportunity. If you pass up something you decline it.

1. Kate is not the sort of person to pass up any opportunity in life. She jumps at every chance she gets.
2. I am trying to lose weight, so I'm going to pass up on the treats going around.
3. This opportunity is too good to pass up.

1. Even though I had a busy schedule, I had to cancel everything when I heard that the American investors wanted to meet me today. This opportunity is too good to pass up!
2. When I saw what the business was going for, I simply had to make a bid. There's no way I could have passed up an offer like that.