Adder rhymes with:
bader, bladder, brader, kadar, ladder, madar, madder, madere, radder, sadder, shadur
Adder sounds like:
adair, adaire, adar, addair, ader, adhere, ador, adora, adore, adoree, adra, adrea, adria, atari, ater, atither, ator, atra, atria, attar, attire, atwater, auditor, auditory, audrey, audrie, audry, autery, auther, authier, author, autrey, autry, awtrey, aydar