de|ci|sive [ dı`saısıv ] adjective **
1. ) making the final result of a situation completely certain:
Gettysburg, site of the final, decisive battle of the Civil War
Cleveland's reputation for reliability was the decisive factor in winning the contract.
The U.S. has played a decisive role in these negotiations.
2. ) able to make choices or decide what to do quickly and confidently:
As a chairperson, he was firm and decisive.
a ) used about someone's behavior:
decisive action: We must take decisive action to solve this problem.
3. ) a decisive victory or defeat is one in which the winner does much better than the LOSER:
a decisive victory for the Democratic Party
╾ de|ci|sive|ly adverb
╾ de|ci|sive|ness noun uncount

Usage of the words and phrases in modern English. 2013.