〜にくい nikui
〜にくい（nikui）means “hard to ~; difficult to ~”. Attaches to the verb ます-stem to say an action is hard to carry out or that something is difficult to do. Formation: V-ます（去ます）+ にくい
hard to ~; difficult to ~
N4Formation
V-ます（去ます）+ にくい
Explanation
Attaches to the verb ます-stem to say an action is hard to carry out or that something is difficult to do. The result behaves like an い-adjective (にくい→にくくない, にくかった). It describes inherent difficulty, often of a thing's usability or a situation, not a one-off failure.
Examples
Note
Its opposite is 〜やすい (easy to ~): のみやすい (easy to swallow).
FAQ
〜にくい — what does it mean and how is it used?
hard to ~; difficult to ~. Attaches to the verb ます-stem to say an action is hard to carry out or that something is difficult to do. The result behaves like an い-adjective (にくい→にくくない, にくかった). It describes inherent difficulty, often of a thing's usability or a situation, not a one-off failure.
〜にくい — how do you form it?
V-ます（去ます）+ にくい
〜にくい — any usage notes?
Its opposite is 〜やすい (easy to ~): のみやすい (easy to swallow).