महाभारतः mahābhārataḥ - book-1, chapter-201, verse-16

ततः पितामहः साक्षादभिगम्य महासुरौ ।
वरेण छन्दयामास सर्वलोकपितामहः ॥१६॥

16. tataḥ pitāmahaḥ sākṣādabhigamya mahāsurau ,
vareṇa chandayāmāsa sarvalokapitāmahaḥ.

16. tataḥ pitāmahaḥ sākṣāt abhigamya mahāsurau
vareṇa chandayāmāsa sarvalokapitāmahaḥ

16. Then, the Grandfather (Brahmā) himself, the progenitor of all worlds, directly approached the two great demons (mahāsura) and offered them a boon.

Words meanings summery:

• ततः (tataḥ) - then (then, thereupon, from there)

• पितामहः (pitāmahaḥ) - Brahmā, the Grandfather (paternal grandfather, creator (Brahmā))

• साक्षात् (sākṣāt) - directly, in person (directly, in person, visibly)

• अभिगम्य (abhigamya) - having approached (having approached, having gone towards)

• महासुरौ (mahāsurau) - the two great demons

• वरेण (vareṇa) - with a boon (with a boon, by a boon, by choice)

• छन्दयामास (chandayāmāsa) - he offered them a boon (he caused to please, he gratified, he offered choice/boon)

• सर्वलोकपितामहः (sarvalokapitāmahaḥ) - the progenitor of all worlds (Brahmā) (progenitor of all worlds, grandfather of all worlds)

Words meanings and morphology

ततः (tataḥ) - then (then, thereupon, from there)

(indeclinable)

पितामहः (pitāmahaḥ) - Brahmā, the Grandfather (paternal grandfather, creator (Brahmā))

(proper noun)

Nominative, masculine, singular of pitāmaha

pitāmaha - paternal grandfather, great father, a name of Brahmā

Note: Refers to Brahmā.

साक्षात् (sākṣāt) - directly, in person (directly, in person, visibly)

(indeclinable)

अभिगम्य (abhigamya) - having approached (having approached, having gone towards)

(indeclinable)

Absolutive/Gerund

from abhi + √gam + lyap suffix

Prefix: abhi

Root: gam (class 1)

महासुरौ (mahāsurau) - the two great demons

(noun)

Accusative, masculine, dual of mahāsura

mahāsura - great demon, powerful demon, mighty asura

Compound type : karmadhāraya (mahā+asura)

• mahā – great, large, mighty
  adjective
• asura – demon, titan, anti-god
  noun (masculine)

Note: Refers to the two Mahāsuras undergoing penance.

वरेण (vareṇa) - with a boon (with a boon, by a boon, by choice)

(noun)

Instrumental, masculine, singular of vara

vara - boon, blessing, choice, best, excellent

Root: vṛ (class 5)

छन्दयामास (chandayāmāsa) - he offered them a boon (he caused to please, he gratified, he offered choice/boon)

(verb)

3rd person , singular, active, perfect (lit) of chand

Causative perfect, 3rd person singular

Root: chand (class 1)

सर्वलोकपितामहः (sarvalokapitāmahaḥ) - the progenitor of all worlds (Brahmā) (progenitor of all worlds, grandfather of all worlds)

(proper noun)

Nominative, masculine, singular of sarvalokapitāmaha

sarvalokapitāmaha - grandfather of all worlds, creator of all worlds

Compound type : tatpurusha (sarvaloka+pitāmaha)

• sarvaloka – all worlds, the entire universe
  noun (masculine)
• pitāmaha – paternal grandfather, Brahmā
  noun (masculine)

Note: An epithet for Brahmā.