[adj] not based on fact or investigation; "a notional figure of cost helps in determining production costs"; "speculative knowledge"
[adj] showing curiosity; "if someone saw a man climbing a light post they might get inquisitive"; "raised a speculative eyebrow"
[adj] not financially safe or secure; "a bad investment"; "high risk investments"; "anything that promises to pay too much can't help being risky"; "speculative business enterprises"
Synonyms
bad, curious, high-risk, inquisitive, insecure, notional, questioning, risky, theoretic, theoretical, unsound, wondering(a)