1. help that allows you to achieve something, or gives you an advantage over others
get a leg-up on rivals/the competition
A leg-up is a noun which refers to an act or gesture intended to help someone to reach or mount a high object. You might give someone a leg-up so they can reach a high shelf or window or so they can reach a horse for example. A leg-up can also be something that is done to help someone else who is in a difficult situation.