thorny (adj.)
- abstruse
- acanthoid
- aciculate
- arduous
- barbed
- barbellate
- brambly
- briery
- bristly
- brutal
- complex
- complicated
- controversial
- critical
- delicate
- demanding
- difficult
- exacting
- formidable
- hairy
- hard
- hard-fought
- intricate
- involved
- knotted
- knotty
- laborious
- mean
- nasty
- nettlesome
- operose
- painful
- prickly
- problematic
- rigorous
- rough
- rugged
- setaceous
- setose
- severe
- spiked
- spinous
- spiny
- steep
- sticky
- stinging
- strenuous
- tangled
- ticklish
- toilsome
- tough
- tricky
- troublesome
- uphill
- vexatious
- wicked
- worrying
Do not, as some ungracious pastors do,
Show me the steep and thorny way to heaven;
Whiles, like a puff'd and reckless libertine,
Himself the primrose path of dalliance treads,
And recks not his own rede.