The term GROW DULL is a phrase that describes something that has become less vibrant or exciting over time. The crossword solutions for this term are PALL (4 letters), TARNISH (7 letters), STAGNATE (8 letters), and LOSELUSTER (10 letters). PALL means to become dull or unexciting, while TARNISH implies a discoloration or fading of something's original luster. STAGNATE means to remain stagnant or inactive, and LOSELUSTER suggests a lack of brightness or vibrancy. All of these words describe the process of something becoming less interesting or attractive over time.