late 14c., "contemplative," also "purely scientific, in theory only" (opposed to practical), from Old French speculatif "worth great attention; theoretical," or directly from Late Latin speculativus, from past participle stem of speculari (see speculation). Meaning "given to (financial) speculation" is from 1763. Related: Speculatively.
raised a speculative eyebrow
speculative business enterprises
speculative knowledge
spectroscope
spectrum
specular
speculate
speculation
speculative
speculator
speculum
sped
speech
speechify