にくい

In a sentence

• この本は理解しにくいです。

  This book is hard to understand.

  Here, 'にくい' is attached to the verb '理解する' (to understand) and implies that the action of understanding is difficult to perform.

• 話しにくい雰囲気を感じました。

  I felt an atmosphere that made it hard to speak.

  In this sentence, 'にくい' attaches to the verb '話す' (to speak), indicating that speaking is challenging due to the atmosphere.

• この靴は歩きにくいです。

  These shoes are difficult to walk in.

  Here, 'にくい' links to the verb '歩く' (to walk), specifying that the act of walking is made difficult by the shoes.