Valmiki Ramayana Yuddha Kanda Sarga 56 Shloka 1
Original Shlokaतद्दृष्टवासुमहत्कर्मकृतंवानरतस्तमैः । क्रोधमाहारयामासयुधितीव्रमकम्पनः ।।6.56.1।।
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अकम्पनः Akampana, युधि in battle, वानरसत्तमैः foremost of Vanaras, कृतम् accomplishment, तत् that, सुमहत् great, कर्म action, दृष्टवा observing, तीव्रम् violent, क्रोधम् angry, आहारयामास exhibiting.
Observing the great action and accomplishment of the foremost Vanaras in the battle, Akampana exhibited violent anger. Hanuman kills Akampana in the fight.