فِي عِيْشَةٍ

فِي عِيْشَةِ is a phrase (شِبْهُ الجُمْلَةِ) consisting of a particle of pulling down (preposition) and a genitive noun

PhraseParticle / NounNoun Particle
شِبْهُ الجُمْلَةِجَارٌ وَمَجْرُوْرٌاسْمٌ مَجْرُوْرٌحَرْفُ جَرٍّ
PhraseCompoundGenitive NounParticle of pulling down
  
in a lifeفِي عِيْشَةٍ=عِيْشَةٍ+فِي
in a lifea lifein
Surah/Below are the 2 verses in the holy Quran containing the preposition and genitive noun compoundفِي عِيْشَةٍ
Verse
69-21he will live a pleasing lifeفَهُوَ فِي عِيْشَةٍ رَّاضِيَةٍ
101-7he will live a pleasing lifeفَهُوَ فِي عِيْشَةٍ رَّاضِيَةٍ