on the spur moment (adverb) extemporaneously: without preparation
Sinonime: clear as dishwater,
cryptic,
doubtful,
dubious,
enigmatic, enigmatical, equivocal, inconclusive,
indefinite,
indeterminate, inexplicit, muddy, multivocal, obscure, opaque, polysemous, puzzling,
questionable, tenebrous, uncertain, unclear, unintelligible, vague
Antonime: clear,
definite,
explicit,
lucid