different between assiduous vs efficacious

English

Etymology

From Latin assiduus from assidere (“to sit down to”), from ad- (“to”) + sedere (“to sit”).

Cognate (via assidere) to assess.

Pronunciation

• (UK) IPA^(key): /??s?dju??s/
• (General American) IPA^(key): /??s?d?u??s/

Adjective

assiduous (comparative more assiduous, superlative most assiduous)

1. Hard-working, diligent or regular (in attendance or work); industrious.

   Synonyms: meticulous, diligent, sedulous; see also Thesaurus:industrious

   • 1917, P. G. Wodehouse, "Bill the Bloodhound" in The Man With Two Left Feet and Other Stories:

     A good deal of assiduous attention had enabled Henry to win this place in her affections.

   • 2009, Will Pavia, "Allen Klein, accountant turned manager of the Beatles, dies at 77," The Times (UK), 6 July:

     Klein rose to prominence in the 1960s by assiduous application of accounting methods to the music industry.

Usage notes

• Since the 18th century, this term has sometimes carried a connotation of servility.

Derived terms

• assiduously
• assiduousness

Related terms

Translations

References

English

Etymology

From Old French efficacieux, from Latin effic?x (“efficacious”) +? -ous, from efficere (“to effect, to accomplish”); see effect.

Pronunciation

• IPA^(key): /?f.?.?ke?.??s/

  Rhymes: -e???s

Adjective

efficacious (comparative more efficacious, superlative most efficacious)

1. (formal) Effective; possessing efficacy. [from 1520s]

   Synonym: effective

   Antonym: inefficacious

Related terms

Translations

Further reading

• efficacious in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913.
• efficacious in The Century Dictionary, New York, N.Y.: The Century Co., 1911.
• “efficacious”, in Lexico, Dictionary.com; Oxford University Press, 2019–present.