To flounder (لڑکھڑانا) means 'to struggle awkwardly' (بے ڈھنگے پن سے کوشش کرنا) as if in mud or water. It can also mean to be in serious difficulty.

Flimsy (کمزور) means insubstantial and easily damaged. A flimsy excuse is weak and 'inadequate' (ناکافی). 'Sturdy' (مضبوط) is the antonym.

To be flabbergasted (حیران رہ جانا) means to be greatly surprised or 'astonished' (ششدہ).

Finicky (نفاست پسند) means fussy or 'choosy' (انتخاب میں سخت) about one's needs or requirements, especially regarding food. 'Easy-going' (ملنسار) is an antonym.

Fidelity (وفاداری) means faithfulness to a person, cause, or belief, demonstrated by continuing loyalty and 'dedication' (لگن). 'Treachery' (غداری) is the antonym.

Fiction (افسانہ) is literature that describes imaginary events and people. It is a 'fabrication' (من گھڑت) or invention. 'Reality' (حقیقت) is the antonym.

Fickle (غیر مستقل مزاج) means 'changing' (بدلتے رہنا) frequently, especially regarding one's loyalties, interests, or affection. 'Steadfast' (ثابت قدم) is the antonym.

A fiasco (ناکامی) is a complete, ridiculous, and ignominious 'failure' (بری طرح ناکامی).

Fervour (جوش) is intense and passionate feeling. 'Eagerness' (شوق) or strong enthusiasm is a key component of this. 'Apathy' (بے حسی) is the antonym.

To ferment (خمیر اٹھنا) is the chemical breakdown of a substance, such as sugar, by microorganisms, which is the process used to 'form alcohol' (شراب بنانا).