deep

adj., n., & adv.
—adj.
1 a extending far down from the top (deep hole; deep water). b extending far in from the surface or edge (deep wound; deep plunge; deep shelf; deep border).
2 (predic.) a extending to or lying at a specified depth (water 6 feet deep; ankle-deep in mud). b in a specified number of ranks one behind another (soldiers drawn up six deep).
3 situated far down or back or in (hands deep in his pockets).
4 coming or brought from far down or in (deep breath; deep sigh).
5 low-pitched, full-toned, not shrill (deep voice; deep note; deep bell).
6 intense, vivid, extreme (deep disgrace; deep sleep; deep colour; deep secret).
7 heartfelt, absorbing (deep affection; deep feelings; deep interest).
8 (predic.) fully absorbed or overwhelmed (deep in a book; deep in debt).
9 profound, penetrating, not superficial; difficult to understand (deep thinker; deep thought; deep insight; deep learning).
10 Cricket distant from the batsman (deep mid-off).
11 Football distant from the front line of one's team.
12 sl. cunning or secretive (a deep one).
—n.
1 (prec. by the) poet. the sea.
2 a deep part of the sea.
3 an abyss, pit, or cavity.
4 (prec. by the) Cricket the position of a fielder distant from the batsman.
5 a deep state (deep of the night).
6 poet. a mysterious region of thought or feeling.
—adv. deeply; far down or in (dig deep; read deep into the night).
Phrases and idioms:
deep breathing breathing with long breaths, esp. as a form of exercise. deep-drawn (of metal etc.) shaped by forcing through a die when cold. deep-fry (-fries, -fried) fry (food) in an amount of fat or oil sufficient to cover it. deep kiss a kiss with contact between tongues. deep-laid (of a scheme) secret and elaborate. deep mourning mourning expressed by wearing only black clothes. deep-mouthed (esp. of a dog) having a deep voice. deep-rooted (esp. of convictions) firmly established. deep sea the deeper parts of the ocean. deep-seated (of emotion, disease, etc.) firmly established, profound. Deep South the States of the US bordering the Gulf of Mexico. deep space the regions beyond the solar system or the earth's atmosphere. deep therapy curative treatment with short-wave X-rays of high penetrating power. go off (or go in off) the deep end colloq. give way to anger or emotion. in deep water (or waters) in trouble or difficulty. jump (or be thrown) in at the deep end face a difficult problem, undertaking, etc., with little experience of it.
Derivatives:
deeply adv. deepness n.
Etymology: OE deop (adj.), diope, deope (adv.), f. Gmc: rel. to DIP