i-adjective
Dated i-adjective form of 同じ. In modern Japanese, 同じ is used as a na-adjective or attributive form, and 同じい is rarely encountered outside older texts or stylized speech.
See also: 同じ
昔の小説には「同じい」という言い方が出てくることがある。
In old novels, the form 同じい sometimes appears.
「同じい」
同じい is an old adjective that is hardly used today.