shad·ow

– noun
1. a dark figure or image cast on the ground or some surface by a body intercepting light.
2. shade or comparative darkness, as in an area.
3. darkness, esp. that coming after sunset.
4. shelter; protection.
5. a slight suggestion; trace.
6. a specter or ghost.
7. a hint or faint, indistinct image or idea; intimation.
8. a mere semblance.
9. a reflected image.
10. a. the representation of the absence of light on a form.
b. the dark part of a picture, esp. as representing the absence of illumination.
11. a dark figure or image cast by an object or part of an object upon a surface that would otherwise be illuminated by the theoretical light source.
12. a period or instance of gloom, unhappiness, mistrust, doubt, dissension, or the like, as in friendship or one's life.
13. a dominant or pervasive threat, influence, or atmosphere, esp. one causing gloom, fear, doubt, or the like.
14. an inseparable companion.
15. a person who follows another in order to keep watch upon that person, as a spy or detective.
–verb
16. to cast a gloom over; cloud.
18. to screen or protect from light, heat, etc.; shade.
19. to follow about secretly, in order to keep watch over his movements.
20. to represent faintly, prophetically, etc.