。
The meaning of this sentence is ambiguous.
Literal
This sentence [gen-の] meaning [topic-は] ambiguous [copula-だ].
曖昧 is a na-adjective meaning 'ambiguous / vague,' commonly used in discussions about language, instructions, or situations with unclear boundaries. A clean, minimal topic-comment sentence — X は Y だ — with no structural complexity. Useful as a vocabulary item more than a grammar model.