straight

Concise Oxford English Dictionary © 2008 Oxford University Press:
straight/streɪt/

▶adjective

• 1 extending uniformly in one direction only; without a curve or bend.

  ■ (of an arch) flat-topped.

• 2 properly positioned so as to be level, upright, or symmetrical.

  ■ in proper order or condition.

• 3 not evasive; honest.

  ■ (of a choice) simple.

  ■ (of thinking) clear and logical.

• 4 in continuous succession.

• 5 (of an alcoholic drink) undiluted.

• 6 (of drama) serious as opposed to comic or musical.

• 7 informal conventional or respectable.

• 8 informal heterosexual.

▶adverb

• 1 in a straight line; directly.

  ■ without delay; immediately.

• 2 in a straight manner.

▶noun

• 1 the straight part of something, especially the concluding stretch of a racecourse.

  ■ archaic a straight form or position.

• 2 Poker a continuous sequence of five cards.

• 3 informal a conventional person.

• 4 informal a heterosexual.

– phrases
go straight live an honest life after being a criminal.
the straight and narrow the honest and morally acceptable way of living.
straight away immediately.
a straight fight Brit. a contest between just two opponents.
straight from the shoulder

• 1 dated (of a blow) swift and well delivered.

• 2 (of words) frank or direct.

straight off (or out) informal without hesitation or deliberation.
straight up informal

• 1 Brit. honestly.

• 2 chiefly N. Amer. undiluted or unadulterated.

– derivatives
straightish adjective,
straightly adverb,
straightness noun.

– origin ME: archaic past part. of stretch.