involving or requiring strenuous effort; difficult and tiring
GMAT
GRE
Formal
See arduous in a sentence written about what you actually care about
Brevlex writes every example sentence around your interests, then schedules it with spaced repetition so it sticks. No generic textbook line — a sentence for you.
GRE Word List 4700 (recognized prep compilation)Recognized
GregMat 960 GRE WordsRecognized
Each source is a real, checkable word list that contains arduous. We never claim an official exam-board list — none is published for the GRE, GMAT, or SAT.