deep

Concise Oxford English Dictionary © 2008 Oxford University Press:
deep/diːp/

▶adjective

• 1 extending far down or in from the top or surface.

  ■ extending a specified distance from the top, surface, or outer edge.

  ■ Cricket (of a fielding position) relatively distant from the batsman.

  ■ (in ball games) to or from a position far down or across the field.

• 2 very intense, profound, or extreme: a deep sleep.

  ■ difficult to understand.

• 3 (of sound) low in pitch and full in tone; not shrill.

• 4 (of colour) dark and intense.

▶noun

• 1 (the deep) literary the sea.

  ■ (usu. deeps) a deep part of the sea.

• 2 (the deep) Cricket the part of the field distant from the batsman.

▶adverb far down or in; deeply.

■ (in sport) distant from the batsman or forward line of one's team.

– phrases
go off the deep end informal give way immediately to an emotional or irrational outburst.
have deep pockets informal have a lot of financial resources.
in deep water informal in trouble or difficulty.
jump (or be thrown) in at the deep end informal face a new and difficult undertaking with little preparation.

– derivatives
deeply adverb,
deepness noun.

– origin OE dēop (adj.), dīope, dēope (adv.), of Gmc origin; rel. to dip.