1. in the sense of durable
- strong
- durable
- resistant
- resilient
- rugged
- sturdy
- solid
- firm
- sound
- substantial
- indestructible
- stout
- hard
- unbreakable
- stiff
- rigid
- toughened
- inflexible
- long-lasting
- hard-wearing
- well built
- heavy-duty
- made to last
2. in the sense of chewy
- leathery
- chewy
- stringy
- gristly
- sinewy
- fibrous
- cartilaginous
3. in the sense of resilient
- strong
- resilient
- gritty
- hardy
- resolute
- determined
- stalwart
- dogged
- fit
- rugged
- powerful
- robust
- doughty
- red-blooded
- cynical
- hardened
- hard
- hard-bitten
- (as) tough as old boots
4. in the sense of arduous
- onerous
- arduous
- demanding
- difficult
- heavy
- hard
- burdensome
- taxing
- exhausting
- tiring
- wearying
- punishing
- laborious
- fatiguing
- exacting
- strenuous
- formidable
- troublesome
- Herculean
- stressful
- exigent
- toilsome
- thorny
- knotty
- tricky
- baffling
- prickly
- ticklish
- puzzling
- perplexing
- bothersome
- mystifying
- intractable
- irksome
5. in the sense of strict
- stern
- strict
- hard
- severe
- firm
- harsh
- adamant
- hard-hitting
- unyielding
- inflexible
- uncompromising
- unbending
- unsympathetic
- unsentimental
- ruthless
- merciless
- hard-hearted
- callous
- cold
- uncaring
- stony
- cool
- flinty
- stony-hearted
- hard-boiled
- hard-nosed
- badass
6. in the sense of rough
7. in the sense of ruffian
Example Sentences of Tough
1. The tough journey tested their endurance.
2. She has a tough decision ahead today.
3. That was a tough exam to pass.
4. He's known for being tough yet fair.