瞎 is very commonly used as an adverb meaning 'blindly/randomly/without basis': 瞎说 (talk nonsense), 瞎猜 (guess randomly), 瞎忙 (busy for nothing), 瞎搞 (mess around). This colloquial usage is far more common than the literal meaning of 'blind'.
mistakes
Using 瞎 for 'blind' can sound informal or blunt. The more respectful terms are 失明 (lost sight) or 视力障碍 (visual impairment).
