にくい・づらい: the difference
にくいN4
Meaning
Difficult to, Hard to
Past papers
Tested once in past papers
Example
甘くないケーキは、食べにくいです。
Cakes that aren't sweet are hard to eat.
づらいN4
Meaning
Hard to, Tough to, Painful to, Difficult to
Past papers
Example
タピオカが大きすぎて吸いづらい。
The tapioca pearls are too big, so they're tough to suck up through the straw.
How to tell them apart
「にくい」 vs 「づらい」 is often tested:
「にくい」 is objective: difficulty caused by the structure of something, the surroundings or skill: 「この肉は硬くて噛みにくい」 (The meat is tough and hard to chew).
「づらい」 is subjective: the speaker feels uncomfortable, awkward or in pain: 「虫歯が痛くて噛みづらい」 (My cavity hurts, so chewing is painful).
For changes a thing itself is unlikely to undergo, such as 「壊れにくい」 and 「割れにくい」, only 「にくい」 works; 「壊れづらい」 sounds unnatural.