V. S. Apte, The Practical Sanskrit–English Dictionary. Look up any word of the Gita in Devanagari, IAST or Harvard-Kyoto, or browse the headwords letter by letter.
Entry अतेजस्
अतेजस्atejasa.Not bright, dim.
[न. ब.]
Not bright, dim.
Weak, feeble.
Insignificant; so अतेजस्क, अतेजस्विन्, -स्Neuter Dimness, shadow, darkness; absence of vigour, feebleness, dullness.