अन्वयः

निर्वेग: without speed (waves), समुद्र: इव like ocean, भग्नदंष्ट्र: bereft of fangs, उरग: इव like snake, उपरक्त: eclipsed by Rahu, आदित्य: इव like Sun, सद्य: suddenly, निष्प्रभताम् devoid of his effulgence, गत: obtained.

M N Dutt

And like to a tideless ocean or a fangless snake, he instantly became shorn of his effulgence, like to the sun overwhelmed by Rahu.* *A Daitya with the tail of a dragon, whose head was served from his body by Vişnu; but being immortal, the head and tail retained their separate existence, and being transferred to the stellar sphere, became the author of eclipses.

Summary

Like the ocean without waves or the snake bereft of fangs or the Sun eclipsed by Rahu, suddenly (Viswamitra) looked cheerless and dull.

पदच्छेदः

इव	इव (अव्ययः)
निर्वेगो	निर्वेग (१.१)
भग्नदंष्ट्र	भग्न (√भञ्ज् + क्त)–दंष्ट्र (१.१)
इवोरगः	इव (अव्ययः)–उरग (१.१)
उपरक्त	उपरक्त (√उप-रञ्ज् + क्त, १.१)–उपरक्त (√उप-रञ्ज् + क्त, १.१)
इवादित्यः	इव (अव्ययः)–आदित्य (१.१)–इव (अव्ययः)–आदित्य (१.१)
सद्यो	सद्यस् (अव्ययः)–सद्यस् (अव्ययः)
निष्प्रभतां	निष्प्रभ–ता (२.१)–निष्प्रभ–ता (२.१)
गतः	गत (√गम् + क्त, १.१)–गत (√गम् + क्त, १.१)

छन्दः

अनुष्टुप् [८]

छन्दोविश्लेषणम्

१	२	३	४	५	६	७	८
सं	दु	र	इ	व	नि	र्वे	गो
भ	ग्न	दं	ष्ट्र	इ	वो	र	गः
उ	प	र	क्त	इ	वा	दि	त्यः
स	द्यो	नि	ष्प्र	भ	तां	ग	तः