unbend
v
(pt, pp unbent )
1 [I, Tn] (cause sth/sb to) become changed from a bent position; straighten (使某物[某人])由弯变直, 弄直, 挺直.
2 [I] (fig 比喻) become relaxed and informal in behaviour 变得轻松和随便
Most professors unbend outside the lecture theatre. 教授在课下大都很随便.