1.definite but not specified or identified;
set aside a certain sum each week
2.having or feeling no doubt or uncertainty; confident and assured;
felt certain of success
3.established beyond doubt or question; definitely known;
what is certain is that every effect must have a cause
4.certain to occur; destined or inevitable;
he was certain to fail
5.established irrevocably;
his fate is sealed
6.capable of being depended on;
a quick and certain remedy
7.exercising or taking care great enough to bring assurance;
be certain to disconnect the iron when you are through