decisive

UK: /dɪˈsaɪsɪv/ US: /dɪˈsaɪsɪv/ ,(di sī′siv)

WordReference Random House Learner's Dictionary of American English © 2026

de•ci•sive /dɪˈsaɪsɪv/   adj. 

1. having the power to decide:
   The decisive argument was the savings his plan would bring.
2. displaying firmness;
   resolute:
   a decisive manner.
3. unquestionable;
   definite:
   a decisive lead of 30-0 by halftime.

de•ci•sive•ly, adv. 
de•ci•sive•ness, n. [uncountable] See -cise-.

WordReference Random House Unabridged Dictionary of American English © 2026

de•ci•sive  (di sī′siv), adj. 

1. having the power or quality of deciding;
   putting an end to controversy;
   crucial or most important:
   Your argument was the decisive one.
2. characterized by or displaying no or little hesitation;
   resolute;
   determined:
   The general was known for his decisive manner.
3. indisputable;
   definite:
   a decisive defeat.
4. unsurpassable;
   commanding:
   a decisive lead in the voting.

• Medieval Latin dēcīsīvus, equivalent. to Latin dēcīs(us) (see decision) + -īvus -ive
• 1605–15

de•ci′sive•ly, adv. 
de•ci′sive•ness, n. 
Synonyms

• 1. conclusive, final.
• 2. firm.

Collins Concise English Dictionary © HarperCollins Publishers::

decisive / dɪˈsaɪsɪv/, decisory / dɪˈsaɪsərɪ/ adjective

1. influential; conclusive
2. characterized by the ability to make decisions, esp quickly; resolute

deˈcisively adverb

deˈcisiveness noun