Walk stiffly is a phrase that describes a type of movement. It is usually used to describe someone who is walking with a sense of purpose and determination. The two crossword solutions for this phrase are STRUT and STALK. STRUT is a verb that means to walk with a proud, confident gait. STALK is a verb that means to walk with a slow, deliberate pace. Both words describe a type of movement that is characterized by a stiff, upright posture.