shadow

Concise Oxford English Dictionary © 2008 Oxford University Press:
shadow/ˈʃadəʊ/

▶noun

• 1 a dark area or shape produced by a body coming between light rays and a surface.

  ■ partial or complete darkness.

  ■ a dark patch or area.

• 2 an air or expression of sadness and gloom.

• 3 a position of relative inferiority or obscurity.

• 4 [with neg.] the slightest trace.

• 5 a weak or inferior remnant or version of something.

• 6 an inseparable attendant or companion.

  ■ a person secretly following and observing another.

• 7 [as modifier] Brit. denoting the opposition counterpart of a government minister.

▶verb

• 1 envelop in shadow; cast a shadow over.

• 2 follow and observe secretly.

  ■ accompany (a worker) in their daily activities for experience of or insight into a job.

– derivatives
shadower noun,
shadowiness noun,
shadowless adjective,
shadowy adjective (shadowier, shadowiest).

– origin OE scead(u)we (n.), oblique case of sceadu (see shade), sceadwian ‘screen or shield from attack’, of Gmc origin.