Natyashastra
स्तब्धं च निम्नपृष्ठं च निर्भुग्नांसं समुन्नतम् । उरो निर्भुग्नमेतद्धि कर्म चास्य निबोधत ॥ २२७॥
The Nirbhugna (unbent) breast is stiff, with the back depressed, shoulders not bent, and raised. It is used in conditions like paralysis, resentment, surprise, asserting truth, haughtiness, and excess pride.
english translation
stabdhaM ca nimnapRSThaM ca nirbhugnAMsaM samunnatam । uro nirbhugnametaddhi karma cAsya nibodhata ॥ 227॥
hk transliteration by Sanscript