adverb, na-adjective
intentionally; deliberately; on purpose
Used when someone does something with conscious intent, often with a nuance of doing it unnecessarily or pointedly.
彼はことさら大きな声で話した。
He spoke in a deliberately loud voice.
ことさら問題を大きくする必要
There's no need to intentionally blow the issue out of proportion.
adverb, na-adjective
Used to single out something as noteworthy, often in negative or contrastive contexts. Less common than the intentional sense.
今日はことさら寒く感じる。
Today feels especially cold.
この点についてはことさら強調しておきたい。
I want to particularly emphasize this point.
わざと is a more common and casual word for 'on purpose', often implying a mischievous or obvious intent. ことさら is more formal and can carry a nuance of doing something unnecessarily or pointedly.
特に is the standard word for 'especially' or 'particularly'. ことさら in this sense is more literary and emphatic, often used in written or formal speech.
Derived from こと (事, 'matter') + さら (更, 'further, again'). The combination originally meant 'on top of the matter' or 'in addition', which developed into the senses of 'intentionally' and 'especially'.