がたい

Attached to a verb, がたい means that an action is very hard or nearly impossible to do. The reason is usually psychological or emotional, such as disbelief, disapproval or reluctance, rather than physical.

がたい belongs to written and formal language and appears in essays, news and formal speech. It typically combines with verbs of thinking, feeling or accepting, such as 信じる, 理解する, 許す, 賛成する and 想像する. It expresses that the speaker finds it almost impossible to accept or carry out the action. It is not used for mere physical or practical difficulty.

• にくいN4Attaches in the same way as「がたい」and is neutral in tone, common in both speech and writing; it means something is hard or awkward to do, or that something does not easily happen (e.g.,「壊れにくい」), and is milder than「がたい」. Use「にくい」when saying an everyday object is awkward to use.
• づらいN4Also attaches to the ます-stem; it describes something as strenuous or awkward to do because of physical discomfort or psychological misgivings — the action itself is possible, and the subjective feeling is strong. It is neutral in register and common in everyday use, whereas「がたい」means nearly impossible and sounds formal.
• かねるN2Also attaches to the ます-stem and conjugates like an ichidan (ru-) verb; it mainly means you are not in a position to do something because of your stance or the rules, and it is often used for polite refusals — it can also express hesitation (「決めかねる」). For 'hard to believe' or 'hard to forgive',「がたい」is more natural.
• ようがない / ようもないN2Also attaches to the ます-form with ます removed (サ変 verbs: 「説明のしようがない」); it stresses that there is not even one way to do it and no place to start, in a neutral register.「がたい」means 'extremely hard to do', often referring to something psychologically hard to accept, and leans toward written style.
• べくもないN1Attaches to the dictionary form and means that, given the situation, the matter is simply out of the question — more categorical and stiffer than「がたい」's 'hard to...'. It usually pairs with a limited set of verbs such as「望む」「知る」「疑う」, so the two should not be swapped freely.
• 得ないN2Also attaches to the ます-stem and leans toward written style, but it does not mean 'hard' — it flatly asserts that something is logically or conditionally impossible, as in the common「あり得ない」.「がたい」means very hard, nearly impossible to do, so the two are generally not interchangeable.

にくい expresses general, often physical or objective difficulty, and づらい expresses personal discomfort or strain. かねる is a polite way of saying the speaker cannot bring themselves to do something. ようがない / ようもない means there is no way or means to do it, 得ない and べくもない state outright impossibility, and がたい means 'nearly impossible to accept or do' for mainly emotional reasons.