Valmiki Ramayana Sundara Kanda Sarga 47 Shloka 30

वीर्यवान् valiant one, महाबलः very powerful, महाकपिः mighty vanara, इति thus, परस्य enemy's, प्रवेगम् speed, चिन्तयन् while reflecting upon, स्वकर्मयोगं च and his own course of action, विधाय after realising, तदा then, वेगम् speed, चकार increased, अस्य his, वधे in killing, मतिं च चक्रे made up his mind.

Reflecting on the power of the enemy, the mighty and valiant vanara thought of his own course of action. Hanuman made up his mind to kill the enemy and increased his speed.