Answer: olddog
AnswerCrossword Clue
OLDDOGProverbial learning-disabled one
OLDDOGIt's hard to teach one new tricks, so they say
OLDDOGPooch beyond trick-learning years, supposedly
OLDDOGProverbial fogy
OLDDOGOne with difficulty learning new tricks, supposedly
OLDDOGNot a prospect for learning new tricks
OLDDOGNew tricks non-learner
OLDDOGUnteachable one, it's said
OLDDOGNew trick resister, supposedly
OLDDOGTray, for one.
OLDDOGStephen Foster's "... Tray"
OLDDOGNonlearner, proverbially
OLDDOGProverbial nonlearner
OLDDOGResister of new tricks