Related Clues:

• Like lightning
• Not ending
• More than diet
• Like some friends
• Word that can precede the first word of 17-, 26-, 43- or 58-Across
• Observe Lent
• Fleet of foot
• See 117-Down
• Immortal
• Firmly fixed
• Never cut off
• Lacking vicissitude
• Type of triangle
• What love can be
• Like a cheetah