Here's what rhymes with welldefinable.
definable indefinable undefinable Words that almost rhyme with welldefinable
desirable viable sizable sizeable decidable liable excitable assignable likable likeable risible liveable deniable reliable advisable undesirable pliable describable survivable undeniable verifiable inadvisable realizable indictable ascribable recyclable certifiable notifiable climbable rectifiable unlikeable unliveable identifiable justifiable unreliable indescribable irreconcilable libidinal classifiable cognizable maniacal reconcilable analyzable unverifiable nonassignable recognizable unjustifiable ammoniacal demoniacal unidentifiable unrecognizable monomaniacal