To infringe (خلاف ورزی کرنا) means to actively 'break' (توڑنا) or violate the terms of a law, agreement, or right (e.g., copyright infringement). 'Forfeit' (ضائع کرنا) means to lose something as a penalty.

Infrastructure (بنیادی ڈھانچہ) refers to the basic physical and 'organizational composition' (تنظیمی ڈھانچہ) needed for a society or enterprise to function (e.g., roads, power, buildings).

Infliction (تکلیف پہنچانا) is the action of imposing something unpleasant or unwelcome on someone. 'Imposition' (نفاذ) is the most direct synonym.

Infinite (لامحدود) means limitless or 'endless' (بے پایان) in space, extent, or size. 'Indefinite' (غیر معینہ) means not clearly defined, which is different.

An infidel (کافر) is an archaic and often derogatory term for a person who does not believe in a particular religion. 'Unbeliever' (بے دین) is the literal definition. 'Conformist' (روایت پسند) is someone who follows established norms.

Infested (بھرا ہوا) means to be present in large numbers, typically so as to cause damage or disease. 'Full of' (سے بھرا ہوا) in a negative context is the closest meaning.

An inference (نتیجہ) is a conclusion reached on the basis of evidence and reasoning. It is a 'reasoned deduction' (منطقی نتیجہ) made from available facts. 'Idea' (خیال) is too general.

To be infatuated (فریفتہ) is to be possessed by an intense but short-lived passion or admiration for someone. 'Fascinated' (سحر زدہ) is a strong synonym. 'Indifferent' (لاپرواہ) is an antonym.

Inevitable (ناگزیر) means certain to happen and unavoidable. It is something 'that must happen' (جس کا ہونا لازمی ہو).

Inertia (جمود) is a tendency to do nothing or to remain unchanged. 'Sluggishness' (سستی) or lethargy is the best synonym. 'Agility' (پھرتی) is the antonym.