(a.) Somewhat like a viper; viperous.

Reptilia Surinam toad aeroboat air airy nothing angiosperm anguine annual aquatic plant batrachian biennial boat seaplane bubble bullfrog caecilian clipper colubriform cosmopolite crawling creeping croaker crocodilian cutting deciduous plant dicot dicotyledon eft ephemeral ether evergreen exotic floatplane flowering plant flying boat frog froggy fungus gametophyte grass frog gymnosperm hellbender hoppytoad hoptoad hydrophyte hydroplane illusion leopard frog lizardlike midwife toad mist monocot monocotyl mud puppy newt ophidian paddock perennial phantom pickerel frog plant polliwog polycot polycotyl polycotyledon repent reptant reptile reptilelike reptilian reptiliform reptiloid salamander saurian seaplane seed plant seedling serpentiform serpentile serpentine serpentlike serpentoid shadow siren slithering smoke snakelike snaky spermatophyte spirit sporophyte spring frog tadpole thallophyte thin air toad toadish tree frog tree toad triennial vapor vascular plant vegetable viperiform viperish viperlike viperoid viperous vipery water dog waterplane weed wood frog