straighten up

: to make straight

: to become straight

: in or into a higher position or level

: from beneath the ground or water to the surface

: from below the horizon

: risen above the horizon

: standing

: being out of bed

used as a function word to indicate motion to or toward or situation at a higher point of

: up into or in the

: in a direction regarded as being toward or near the upper end or part of

: one in a high or advantageous position

: an upward slope

: a period or state of prosperity or success

: to rise from a lying or sitting position

: to move upward : ascend

used with and and another verb to indicate that the action of the following verb was either surprisingly or abruptly initiated