'Competitiveness' is always abstract: 'The thing he most liked about her was her competitiveness.' 'Your CV lists "competitveness" as one of your strengths. How do you think other people see that?'
(You'd normally get one chance to be lazy like this, but I had nothing better to do! You'll find that on this site people prefer you to use a dictionary - and then ask any question that arises. )