unbend
v.
mid-13c., "relax a bow by unstringing it," from un-(2) "reverse, opposite of" + bend, v.. Intransitive sense from 1746. Figurative meaning "to become genial, relax" (1748) has a sense opposite to that of unbending "inflexible, obstinate" (1680s), which does not derive from the bow-stringing image.
〔李〕[un-=to undo取消；bend v.弯 →“to undo that of bend-ing取消弯曲的状态”→] v.①straighten弄直；伸直