give a start

It means a quick, startled movement.

hi
i can say that kind of expression " what a start they gave! "
for the word "start " it's clear it means begin.
now, in the expression ,I think the meaning is changed..it doesn't mean only a begening of something..but it means more than that.
the expression in this case is showing how is the begining...usually it's expressing a best start that could occur ...something we don't expect,
like if you are a fun of soccer,when the team beggin to play very fast...which unsual to see in other matches...
i hope my paragraph is helping