speculative (adj.)

• abstract
• academic
• adventurous
• aleatory
• analytical
• arguable
• chancy
• cogitative
• cognitive
• conceptive
• conceptual
• confutable
• conjectural
• contemplative
• contestable
• controversial
• controvertible
• curious
• debatable
• deliberative
• deniable
• dicey
• disputable
• doubtable
• doubtful
• dubious
• dubitable
• hazardous
• hypothetic
• hypothetical
• ideal
• idealistic
• idealized
• ideational
• iffy
• impractical
• inquiring
• intellectual
• introspective
• meditative
• mental
• mistakable
• moot
• musing
• noetic
• notional
• pensive
• pondering
• prehensive
• problematic
• questionable
• questioning
• ratiocinative
• rational
• reflecting
• reflective
• refutable
• risky
• ruminant
• ruminative
• serious
• sober
• suppositional
• supposititious
• suspect
• suspicious
• theoretical
• thinking
• thought
• thoughtful
• uncertain
• unproved
• unproven
• unrealistic
• unreliable
• untested
• untrustworthy
• venturesome
• venturous
• wildcat
• wistful