~難い (hard to do)

The suffix ~難い (read がたい; also commonly written in kana as ~がたい), attached to a verb stem, meaning 'hard to X / difficult to X'. Formal/written register — 信じ難い ('hard to believe'), 言い難い ('hard to say'), 忘れがたい ('unforgettable'). Contrast with the more common ~にくい (casual/neutral register) and ~づらい (personal-discomfort nuance). The classical predicative form is 難し (がたし).