also: いいがたい
i-adjective
hard to say; inexpressible; difficult to put into words
Used when something is inherently difficult to express verbally, not just because of social hesitation. Often for abstract feelings or complex ideas.
その美しさは言葉では言いがたい。
That beauty is hard to put into words.
今の気持ちはなんとも言
My current feelings are really hard to express.
i-adjective
embarrassing to say; delicate; awkward to mention
Used when social or emotional reasons make something hard to say, such as embarrassment, delicacy, or fear of hurting someone. Often written 言いにくい.
本当のことを言うのは言いにくい。
It's awkward to tell the truth.
給料の話はちょっと言いにくいですね。
Talking about salary is a bit delicate, isn't it?