تَصْلَى

A word in the Arabic language will either be: 1) a verb or 2) a noun or 3) a particle – تَصْلَى is a verb

A verb will either be: 1) past tense or 2) present or future tense or 3) a command or request verb, also called an imperative – تَصْلَى is a present tense verb

A present or future tense verb will be in one of the following states: 1) مَرْفُوْعٌ – nominative or 2) مَنْصُوْبٌ – accusative or 3) مَجْزُوْمٌ – jussive

تَصْلَى is the natural state of this verb, which means it is in the nominative state (مَرْفُوْعٌ) and it remains in this state when it is not preceded by an accusative or jussive particle. Present or future tense verbs show their nominative state by 1) the presence of dammah in its ending or 2) by the presence of ن in the case of dual and plural verbs or 3) by estimation in the case of weak verbs (verbs ending in ي or و)

He shall enter (a blazing fire), will roast

To warm at the fire, endure the heat of fire, put a thing near or upon the fire, roast

 Grammatical analysis of يَصْلَى
 فِعْلٌ مُضَارِعٌ مَرْفُوْعٌ بِالضَّمَّةِ المُقَدَّرَةِ 
مُعْتَلُّ الَّامِالْغَائِبُ هُوَ  النَّاقِصُفِعْلٌ تَامٌّص ل يصَلِيَ يَصْلَى أَو صَلَى يَصْلِيبَابٌ سَمِيَ
Weak 3rdSubject HeWeak VerbComplete VerbRootس / ضاَلْمَصْدَرُ
فِعْلٌ
Verb of command/Requestفِعْلُ أَمْرٍPresent and future tense verbفِعْلٌ مُضَارِعٌPast tense verbفِعْلٌ مَاضٍ
He burns / He will burn/roast/endureيَصْلَىHe burnt/roasted/enduredصَلِيَ
They two burnيَصْلَيَانِThey two burntصَلِيَا
They burnيَصْلُوْنَThey burntصَلُوْا
She burnsتَصْلَىShe burntصَلِيَتْ
They two (feminine) burnتَصْلَيَانِThey two (feminine) burntصَلِيَتَا
They all (feminine) burnيَصْلَيْنَThey all (feminine) burntصَلِيْنَ
Burn/roast اِصْلَYou burnتَصْلَىYou burntصَلِيْتَ
Burn (You two)اصْلَيَاYou two burnتَصْلَيَانِYou two burntصَلِيْتُمَا
Burn (You all)اصْلَوْاYou all burnتَصْلَوْنَYou all burntصَلِيْتُمْ
Burn (feminine)اصْلَيْYou (feminine) burnتَصْلِيْنَYou (feminine) burntصَلِيْتِ
Burn (You two feminine)اصْلَيَاYou two (feminine) burnتَصْلَيَانِYou two (feminine) burntصَلِيْتُمَا
Burn (You all feminine)اصْلَيْنَYou all (feminine) burnتَصْلَيْنَYou all (feminine) burntصَلِيْتُنَّ
I burnأصْلَىI burntصَلِيْتُ
We burnنَصْلَىWe burntصَلِيْنَا

 

Surah/Below is the only verse in the holy Quran containing the imperfect, third person, singular verbتَصْلَى
Verse
17-18They will enter in the hot blazing fireتَصْلَى نَارًا حَامِيَةً