अवाच्यवादांश्च बहून् वदिष्यन्ति तवाहिताः। निन्दन्तस्तव सामर्थ्यं ततो दुःखतरं नु किम् ॥

avāchya-vādānśh cha bahūn vadiṣhyanti tavāhitāḥ nindantastava sāmarthyaṁ tato duḥkhataraṁ nu kim

Many unseemly words will be spoken by thine enemies, slandering thy strength; what more painful than that?

In plain words: Krishna says Arjuna's enemies will mock him and say cruel things about his strength. He asks what could hurt more than that.