Sūtra 1-43
स्मृतिपरिशुद्धौ स्वरूपशुन्येवार्थमात्रनिर्भासा निर्वितर्का। (४३)
Smṛtipariśuddhau svarūpaśūnyevārthamātranirbhāsā nirvitarkā.
(Smṛti-pari-śuddhau svarūpa-śūnya-iva artha-mātra-nirbhāsā nirvitarkā) (43)

When the memory is pure, the illumination of just the object (in the mind), appearing as though it were not there, is deliberation-free sāmadhi.

Sūtra words
Smṛti-pari-śuddhau, svarūpa-śūnya-iva, artha-mātra-nirbhāsā, and nirvitarkā.

Word Formation
Smṛti-pari-śuddhau Seventh case singular, feminine gender of the compound smṛti-pari-śuddhi. The component words of this sixth case tatpuruṣa compound are smṛti and pari-śuddhi. Smṛti, a feminine gender noun is formed from the verb smṛ and suffix ti. Pari-śuddhi, also a feminine gender noun is similarly derived from the verb śuddh with suffix ti and prefix pari.
svarūpa-śūnya-iva This compound is an indeclinable formed from svarūpa-śūnya and the indeclinable iva. Svarūpa-śūnya itself is a sixth case tatpuruṣa compound formed from svarūpa and śūnya; svarūpa is a compound comprising sva and rūpa.
artha-mātra-nirbhāsā Feminine gender first case singular form of a type of tatpuruṣa compound artha-mātra-nirbhāsa, whose component words are artha-mātra and nirbhāsā. The compound artha-mātra consists of two words artha and mātra. Nirbhāsā is formed from the verb bhăs with prefix nis and suffixes a and ā.
nirvitarkā is formed from the verb tarc with prefixes nis and vi and suffixes a and ā.

Word meaning
Smṛti-pari-śuddhau When the memory is pure
svarūpa-śūnya-iva as though devoid of its nature
artha-mātra-nirbhāsā clear illumination of just the object
nirvitarkā is a samādhi that is completely free of deliberative analysis.
(The word samāpatti, that is, samādhi flows from 1-42).

• tarka means deliberation, logical analysis backed by inference. Vitarka, with the prefix vi emphasizes the process of deliberation. With another prefix sa the word savitarka in the previous aphorism is the kind of samādhi which is backed by deliberative process of knowing the object of contemplation. Continued practice of this savirarka-samādhi leads to a state in which there is no longer a need for this deliberative process since the memory is pure, that is free of doubt, error etc., and, this is called nirvirarka-samādhi. Note the anuvṛtti of samāpatti (synonymous with samādhi) from the previous aphorism.