Shloka 5.63.6
दधिमुख-विज्ञापनम् / Dadhimukha Reports the Madhuvana Incident
शिष्टमत्रापविध्यन्ति भक्षयन्ति तथापरे।निवार्यमाणास्ते सर्वे भ्रुवो वै दर्शयन्ति हि।।।।
śiṣṭamatrāpavidhyanti bhakṣayanti tathāpare | nivāryamāṇāste sarve bhruvo vai darśayanti hi ||
Some cast the leftovers away here, while others keep on eating. And when the guards try to restrain them, they all knit their brows, showing open defiance.
"Some have thrown off the leftovers, when others were prevented from drinking off the honey, they raised their eyebrows (to show their grouch).
The Vanaras are celebrating the successful mission of finding Sita. Upon entering the Madhuvana (Honey Grove) protected by Dadhimukha, they become intoxicated with joy and honey, leading to unruly behavior.
In this context, showing or raising eyebrows signifies arrogance, aggression, and defiance against the guards who were attempting to stop them from destroying the grove.