挺直

tǐngzhí
  1. upright; erect
  2. to straighten up (one's back etc); to hold erect

CEDICT

  1. erect; straight
  2. to straighten up (one's body); to hold erect

Wiktionary

直立不弯曲。

重編國語辭典

Entry Composition

1 挺 tǐng
  1. straight
  2. erect
  3. to stick out (a part of the body)
  4. to (physically) straighten up
  5. to support
  6. to withstand
  7. outstanding
  8. (coll.) quite
  9. very
  10. classifier for machine guns
2 直 zhí
  1. straight
  2. to straighten
  3. fair and reasonable
  4. frank
  5. straightforward
  6. (indicates continuing motion or action)
  7. vertical
  8. vertical downward stroke in Chinese characters