noun

the act of ordering or allowing someone to leave.

their controversial dismissal from the competition

one’s notice,discharge,redundancy,expulsion,ousting,the sack,sacking,firing,laying off,the push,the boot,the axe,the (old) heave-ho,one’s marching orders,defenestration,the elbow,turfing out,one’s cards,the chop,cashiering,rejection,repudiation,refusal,repulse,non-acceptance,snub,slight,pooh-poohing,brush-off,knock-back