adverb
rather; might as well; better just
Used when choosing a more decisive, often somewhat drastic option: 'rather than doing this halfway, it would be better to just ...'. Common with forms such as いっそ〜しよう, いっそ〜したほうがいい, and いっそ〜してしまう.
中途半端に直すより、いっそ全部やり直そう。
Rather than fixing it halfway, let's just redo the whole thing.
If you're that unsure, you might as well turn it down.
adverb
if anything; on the contrary; almost rather
Used when an extreme or unexpected situation produces the opposite impression from what one might expect, often with evaluative adjectives such as 清々しい or 気持ちいい.
ここまで徹底していると、いっそ気持ちがいい。
When it is this thorough, it is, if anything, satisfying.
彼の開き直った態度は、いっそ清々しかった。
His defiant attitude was almost refreshing, if anything.