Rig Veda 8.14.13

Sanskrit text [Accents, Plain, Transliterated]:

अ॒पां फेने॑न॒ नमु॑चे॒: शिर॑ इ॒न्द्रोद॑वर्तयः । विश्वा॒ यदज॑य॒: स्पृध॑: ॥
अपां फेनेन नमुचेः शिर इन्द्रोदवर्तयः । विश्वा यदजयः स्पृधः ॥
apām phenena namuceḥ śira indrod avartayaḥ | viśvā yad ajayaḥ spṛdhaḥ ||

English translation:

“You have struck off, Indra, the head of Namuci with the foam of the waters, when you had subdued allyour enemies.”

Commentary by Sāyaṇa: Ṛgveda-bhāṣya

Namuci: legend from śalya parvan, Mahābhārata: Indra after defeating the asuras wascaptured by Namuci. Namuci however, liberated him on the condition that he would not kill him with any weapon,dry or wet, nor by day or night. In evasion of his oath, Indra at twilight, or in a fog, decapitated Namuci with thefoam of water; cf. Taittirīya Saṃhitā 1.8.7

Details:

Ṛṣi (sage/seer): goṣūktyaśvasūktinau kāṇvāyanau;
Devatā (deity/subject-matter): indra:;
Chandas (meter): gāyatrī;
Svara (tone/note): Swar;

Padapatha [Accents, Plain, Transliterated]:

अ॒पाम् । फेने॑न । नमु॑चेः । शिरः॑ । इ॒न्द्र॒ । उत् । अ॒व॒र्त॒य्चः । विश्वाः॑ । यत् । अज॑यः । स्पृधः॑ ॥
अपाम् । फेनेन । नमुचेः । शिरः । इन्द्र । उत् । अवर्तय्चः । विश्वाः । यत् । अजयः । स्पृधः ॥
apām | phenena | namuceḥ | śiraḥ | indra | ut | avartaycaḥ | viśvāḥ | yat | ajayaḥ | spṛdhaḥ

Multi-layer Annotation of the Ṛgveda

[Rigveda 8.14.13 English analysis of grammar]