grueling

[groo-uh-ling, groo-ling]
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noun
  1. any trying or exhausting procedure or experience.
Also especially British, gru·el·ling.

Origin of grueling

1850–55; slang gruel punishment (noun), punish (v.) + -ing2, -ing1
Related formsgru·el·ing·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018