The term 'A Sudden Desire' can be broken down into four crossword solutions: URGE (4 letters), Whim (4 letters), IMPULSE (7 letters), and YEN (3 letters). URGE is defined as a strong feeling of wanting to do something, while Whim is an unpredictable or sudden desire. IMPULSE is an instinctive URGE to act, and YEN is a strong feeling of longing or craving. All of these words describe a sudden, strong desire to do something.