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willpower

[wil-poh-er] / ˈwɪlˌpoʊ ər /
NOUN
personal determination
Synonyms
STRONGEST
firmness grit self-control self-discipline
STRONG
discipline drive fixity force resolution resolve self-government self-restraint single-mindedness strength will
Antonyms
STRONGEST
weakness
STRONG
indecision question

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.