grueling (adj.)
- annoying
- arduous
- backbreaking
- bothersome
- burdensome
- corrective
- crushing
- disciplinary
- draining
- effortful
- enervating
- enfeebling
- exhausting
- forced
- hard-fought
- heavy
- hefty
- irksome
- killing
- labored
- laborious
- onerous
- operose
- oppressive
- painful
- penal
- plaguey
- punishing
- punitive
- punitory
- retributive
- strained
- straining
- strenuous
- stressful
- tiresome
- tiring
- toilsome
- tough
- troublesome
- trying
- uphill
- vexatious
- weakening
- wearing
- wearisome
- wearying
