adverb, noun which may take the genitive case particle 'no', na-adjective
Expresses a moderate degree; often used when the speaker feels something is more than expected or worth noting. Slightly formal or literary in tone compared to ちょっと or 少し.
その提案にはいささか疑問を感じる。
I have some doubts about that proposal.
I'm a bit tired, so let's take a short break.
彼の説明はいささか不十分だった。
His explanation was somewhat insufficient.