वितर्कविचारानन्दास्मितारूपानुगमात्  संप्रज्ञातः । (१-१७) Vitarkavicārānandāsmitārūpānugamāt saṁprajñātaḥ. (1-17)
(Vitarka-vicāra-ānanda-asmitā-rūpa-anugamāt saṁprajñātaḥ)
(The samādhi is called) Saṁprajñāta because it is accompanied by
vitarka, vicāra, ānanda, and asmitā.

Analysis of the words of the aphorism This sūtra has just two words, and the verb of being is understood. The first long word, however, is a compound comprising six word subunits. The long compound Vitarkavicārānandāsmitārūpānugamāt is formed from three compounds, another instance of a compound within a compound within a compound. This device allows for brevity of expression but results in a lengthy translation. First a compound is formed from the words vitarka, vicāra, ānanda and asmitā. This “vitarkavicārānandāsmitā” forms another compound with rūpa. The resulting compound “vitarkavicārānandāsmitārūpa” is combined with anugama to form the final compound and this is declined in the fifth case. Based on the formation of compounds, to understand the meaning, one has to treat each one of the four words vitarka, vicāra, ānanda and asmitā with rūpa and anugamāt.

Vitarka is derived from the verb tark (to reason), with prefix vi and suffix a, meaning reasoning, analysis, deliberation. Here the prefix vi is used to accentuate the verb meaning, ‘intense deliberation’. Note the same word vitarka is used later in sūtras (2-33, 34) with an altogether different meaning, ‘perverse thoughts or thoughts contrary to logical reasoning’. This is made possible by the fact that the same prefix has more than one meaning. For the right meaning one has to depend on primary commentaries and expositions to the aphorisms.
Vicāra  is from the verb car (to move), with prefix vi and suffix a, has a similar meaning to vitarka and is here used here to imply reflection (without analyzing pros and cons of statements pertaining to an object).
Ānanda  is from the verb nand (to rejoice), with the prefix ā and suffix a, meaning joy / bliss. Asmitā is an interesting word that formed by addition of the suffix tā to the verb asmi (I am). The addition of this suffix is equivalent to the suffix “-ness” that is added to adjectives in English. Thus the word means I am-ness – as that is the cognizer. Though Patañjali defines asmitā as ‘the feeling of oneness between the power of the seer (dṛk), and the power of seeing’ (dṛśya) as one of the afflicted mental modes (kliṣṭa-vṛttis) (2-6), the same word does not have the same connotation of affliction here (Śaṅkara’s gloss).
The word rūpa is generally translated as form or color. Here, however, it is used in the sense of ‘merely / solely’ (Śaṅkara’s gloss).
The word anugama, formed from the prefix anu, verb gam (to go) and the suffix a, has the meaning ‘following, accompanying’.
Hence the compound as a substantive means “accompanying merely by vitarka, vicāra, ānanda and asmitā”. The fifth case here is not used in the usual sense of the preposition ‘from’. But it is used in a special sense of cause or motive, so based on this special case meaning the word is translated as ‘because of being accompanied by solely by vitarka, vicāra, ānanda and asmitā’.

Saṁprajñātaḥ is the second word of this aphorism. Saṁprajñāta  is derived from the verb jñā (to know) with two prefixes sam and pra (both accentuate the meaning of the verb) and the suffix ta. Etymologically this word means ‘very well known’. That is, the knower-known duality is implicit. Contextually this word indicates the presence of the seed, I-ness centered subtle impressions in the mind of the one who is in this state of samādhi. But nirbījasamādhi, the final goal of a yogin, is also known as asaṁprajñātasamādhi. This is one of the many places where the technical meaning is more important than etymology, the latter merely providing a better insight.

One must note here that the following terms are synonymous – nirbījasamādhi and asaṁprajñātasamādhi: sabījasamādhi and saṁprajñātasamādhi: samāpatti, samādhi and yoga. In translating the sūtra we added  a few words parenthetically so as to represent the meaning correctly. Patañjali devotes a few sūtra-s (1-42 to 1-46) defining two of the component words of the compound – vitarka and vicāra.