Possible Clues:

• Proverbial nonlearner
• ` `You can't teach an ... ... new tricks' '
• New tricks non-learner
• Slow learner?
• One whose trick-learning years are behind them
• Unlikely learner of new tricks
• ''You can't teach an ... ... new tricks''
• You cannot teach an . . . . . . new tricks''
• Too beastly ancient to be receptive of 27 across
• ''You can't teach an . . . . . . new tricks''