Allah the Exalted narrates to us the story of Fir`awn and his people. A Messenger came to them from Allah, Musa supported by his brother Harun. Their Messengers delivered good news if they believe, and a warning if they rejected the Message. Allah supported Musa and Harun with tremendous miracles and great signs, but Fir`awn and his people rejected all of them. Allah took them the way the All-Mighty, the All-Capable would; He destroyed them all leaving none surviving to tell the story of what happened to them. Advising and Threatening the Quraysh Allah said,
أَكُفَّـرُكُمْ
(Are your disbelievers) meaning, `O idolators of the Quraysh,'
The word زُبُر zubur (in verse 43) is the plural of zabur, which stands for any written book. It specifically refers to the Scripture that was revealed to Prophet Dawud (علیہ السلام) .
أَدْهَىٰ وَأَمَرُّ (...more calamitous and more bitter...54:46). The word adha means more or most calamitous. The word amarr is derived from murr which originally means 'bitter'. By extension anything 'difficult' or 'painful' is also referred to as amarr and murr. In the phrase فِي ضَلَالٍ وَسُعُرٍ fi dalalin wa su'ur, dalal, as is known, means 'error' or 'deviation' and the word su'ur in the present context means the 'Hell-Fire1.' In the phrase ashya'akum, (verse 51) ashya` is the plural of shi'ah, and it means a 'follower', that is, those who follow their pattern of life.
(1). This is according to one interpretation. The other meaning of the word is 'madness' and the translation in the text is based on this meaning. (Muhammad Taqi Usmani
In the phrase مَقْعَدِ صِدْقٍ maq` adi-sidqin, the word maq'ad means 'seat' and the word sidq means 'truth' and implies the 'seat of truth' where there will be no idle and obscene talks.
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 42–47
Pharaoh was a very powerful ruler of his time, but on rejecting the truth he became valueless in the eyes of God. Thereafter, he was killed like any other helpless man. In this world, a man standing out against the Truth renders himself weak.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.