Sanskrit
अयुक्तः प्राकृतः स्तब्धः शठो नैष्कृतिकोऽलसः । विषादी दीर्घसूत्री च कर्ता तामस उच्यते ॥ २८ ॥
ayuktaḥ prākṛtaḥ stabdhaḥ śaṭho naiṣkṛtiko'lasaḥ viṣādī dīrghasūtrī ca kartā tāmasa ucyate
Translation
Discordant, vulgar, stubborn, cheating, malicious, indolent, despairful, procrastinating, that actor is called dark.
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
The tamasic actor is undisciplined, vulgar, obstinate, deceitful, malicious, lazy, prone to despair, and chronically procrastinating — the longest and most granular vice-list in the passage, which suggests tamas was regarded as needing the most explicit naming, perhaps because its symptoms are more easily mistaken for ordinary personal failing than for a spiritual category.