おそくまで

until late

→ 遅い
phrase Rare #37,837
until late Used for continuing up to a late time, often at night. おそく is a casual spelling of 遅く.
JA: 昨日はおそくまで勉強していました。
EN: I studied until late yesterday.

私は彼とおそくまで話し合った

I discussed things with him until late at night.

おそくまで外出していた言い訳をする

I make excuses for staying out late.

おそくまで

until late

— 東京物語 (1953)