Synonyms for Assiduous:

adj.

active (adjective)
active, sedulous, dynamic, vivacious, lively, eager, animated, stirring, spirited, industrious, sprightly, bustling, busy, tireless, enterprising, energetic, moving.
all (adjective)
sedulous.
hard-working (adjective)
busy, persevering, industrious, sedulous, diligent, studious, attentive, active.
hardworking (adjective)
industrious.

n.

meticulous, methodical, painstaking, systematic, exact, thorough, organized, cautious, provident. studious. assiduous (noun)
sedulous, diligent.
industrious (noun)
careful, persevering, study atdiligent, attentive.

Other synonyms:

careful. industrious
studious.
Other relevant words:
meticulous, thorough, diligent, studious, painstaking, cautious, systematic, attentive, persevering, provident, exact, methodical, organized, careful.

Usage examples for assiduous

  1. Milburd and Cazell are most assiduous in their attentions to Miss Bobyns, in order that she may be 'quite warm' before she starts. – Happy-Thought Hall by F. C. Burnand
  2. She remembered Mary's tender and assiduous nursing all the morning, and how she had already stayed from service and Sunday school; and she recollected her honour for her friends for not valuing her for her rank; and in that mood she looked out the Psalms and Lessons, which she had not been able to read in the morning, and when she had finished them, began to examine the book- case in search of a new, or else a very dear old, Sunday book. – Countess Kate by Charlotte M. Yonge