العُسْرَى

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

A noun may either be 1) Definite or indefinite 2) Masculine or feminine 3) Singular, dual or plural 4) Nominative, accusative or genitive

العُسْرَى is the natural state of this definite noun and it remains العُسْرَى even though it is in the genitive case due to: 1) a preposition that precedes it or 2) a possessed noun that precedes it or 3) it’s a noun of dependent declension a) نَعْتٌ / صِفَطٌ adjectives b) التَّوْكِيْدُ emphatic c) المَعْطُوْفٌ conjunction d) البَدَلُ synonym

The final letter in this feminine nominal pattern العُسْرَى is a weak letter (ي) weak letters do not show their endings, their endings have to be estimated (deduced by reason)

Hardship and distress

To be difficult, hard

Surah/Below is the only verse in the holy Quran containing the genitive nounالعُسْرَى
Verse 
92-10then We will facilitate him towards difficultyفَسَنُيَسِّرُهُ لِلْعُسْرَى