EFFICACIOUSNESS Definition & Meaning | Dictionary.com

Featured
Games
Cultural
Writing tips

Dictionary.com

Thesaurus.com

Search Results

Popular Searches

efficaciousness

a word derived from efficacious.

Popular Searches

chonky
throw in the towel
ultimate
impute
YOLO
resilient
voxel

Word of the Day

barnstorm

[bahrn-stawrm]

Over 500,000 expert-authored dictionary and thesaurus entries

Entry list Careers Contact us Help Cookies, terms & privacy

IXL Learning's Dictionary Media Group reaches over 500,000,000 learners each year

Essential reference for synonyms and antonyms

Adaptive learning for English vocabulary

Fun daily word games

English dictionary and learning for Spanish speakers

Spanish-English dictionary, translator, and learning

French-English dictionary, translator, and learning

Immersive learning for 25 languages

Comprehensive K-12 personalized learning

Marketplace for millions of educator-created resources

35,000+ worksheets, games, and lesson plans

Fun educational games for kids

Trusted tutors for 300+ subjects

Math games and learning resources for kids

© 2026 Dictionary Media Group, Inc., a division of IXL Learning