This is a charade with deletion - multiple parts are combined together, with one letter removed from one of the components.
Look for: O (abbreviation for 'old'), P (musical notation for 'piano'), and 'erratic' (meaning unpredictable) with one R removed (since R can stand for 'right'). Combine these elements in order.
Answer: OPERATIC | O (old) + P (piano) + ERatic (unpredictable with one R for 'right' removed) = OPERATIC