وَمَا هَٰذِهِ ٱلْحَيَوٰةُ ٱلدُّنْيَآ إِلَّا لَهْوٌ وَلَعِبٌ وَإِنَّ ٱلدَّارَ ٱلْـَٔاخِرَةَ لَهِىَ ٱلْحَيَوَانُ لَوْ كَانُوا۟ يَعْلَمُونَ
"This life of the world is only a diversion and a game. The abode of the hereafter — that is the real life — if only they knew."
The lexicographers record that this pattern conveys intensification and completeness: "life itself, the fullest state of being alive". The word occurs only here in the Qurʾān.
And the word order must be recorded: wa inna'd-dāra'l-ākhirata la-hiya al-ḥayawān — emphasis by means of the pronoun of separation (hiya). That is, not "there is life in the abode of the hereafter" but: "that is the real life."
I record this as my own reading: the sentence is not making a comparison — it is laying the definition down anew. The life of this world is named with the word life (al-ḥayātu'd-dunyā), but the real life is given to another word.
لَهْوٌ وَلَعِبٌ — the root ل-ه-و was treated at Luqmān 31/6 (lahwa'l-ḥadīth) and at al-Ḥadīd. I do not repeat it here.