noun which may take the genitive case particle 'no'
legal; legally; de jure
Used to describe something from a legal perspective, often contrasting with practical or factual situations. Common in formal or technical contexts.
法律上は問題ないが、倫理的にはどうだろうか。
Legally there is no problem, but ethically, I wonder.
彼は法律上
He was held legally responsible.
事実上 means 'in fact' or 'de facto', often used in contrast with 法律上 (de jure).
Compound of 法律 (ほうりつ, 'law') and the suffix 上 (じょう, 'from the standpoint of'). The suffix 上 is productive and attaches to nouns to form adverbial expressions.