Chapter 18 · Liberation through Renunciation · Krishna said
Bhagavad Gita 18.28 — Tamasic doer
अयुक्तः प्राकृतः स्तब्धः शठो नैष्कृतिकोऽलसः। विषादी दीर्घसूत्री च कर्ता तामस उच्यते ॥
ayuktaḥ prākṛtaḥ stabdhaḥ śaṭho naiṣkṛtiko'lasaḥ | viṣādī dīrghasūtrī ca kartā tāmasa ucyate ||
Meaning
A doer who is undisciplined, crude, stubborn, deceitful, spiteful, lazy, gloomy and always putting things off is called tamasic.