Synonyms of speculative in English:

speculative


See US English definition of speculative

See UK English definition of speculative

See Spanish definition of especulativo

adjective

1‘any discussion of the question is largely speculative’

SYNONYMS
conjectural, suppositional, theoretical, hypothetical, based on guesswork, putative, academic, notional, abstract
tentative, unproven, untested, unfounded, groundless, unsubstantiated
rare ideational, suppositious, suppositive
ANTONYMS

proven

2‘a speculative investment’

SYNONYMS
risky, hazardous, unsafe, uncertain, unpredictable
informal chancy, dicey, iffy
British informal dodgy
ANTONYMS

safe