Longman Dictionary of Contemporary English - spur

~1 n 1 a sharp pointed object on the heel of a rider's boot which is used to encourage a horse to go faster 2 a fact or event that makes you try harder to do something  (Did your father's success act as a spur when you started in business?) 3 do sth on the spur of the moment to do something suddenly, without thinking about it before you do it  (On the spur of the moment she picked up the phone and called Mike.)  (- see also spur­of­the­moment) 4 a piece of high ground which sticks out from the side of a hill or mountain 5 a railway track or road that goes away from a main line or road 6 the stiff sharp part that sticks out from the back of a male chicken's leg ~2 v spurred, spurring 1 also spur on to encourage someone to try harder in order to succeed  (spur sb (on) to)  (It's unlikely that harsh criticism will spur a child on to greater efforts. | spur sb into action (=to make someone start doing something)) 2 to make an improvement or change happen faster  (Lower taxes would spur investment and help economic growth.) 3 to encourage a horse to go faster, especially by pushing it with special points on the heels of your boots