Questions & Answers about kono kanji wa kakinikui desu.
書きにくい means “difficult to write” or “hard to write.”
It’s formed by taking the verb stem 書き (from 書く, “to write”) and adding the suffix にくい, which creates an i-adjective expressing that an action is hard to do.
In this sentence 書きにくい is an adjective, not the verb 書く. The structure is:
Topic (この漢字) + は + i-adjective (書きにくい) + です.
Since it’s an adjective phrase (“hard to write”), you don’t use the object marker を here.
