The word(s) "doubt" appears 53 time(s) in 51 verse(s) in Quran in Muhammad Habib Shakir translation.

(41) And they did not become divided until after knowledge had come to them out of envy among themselves; and had not a word gone forth from your Lord till an appointed term, certainly judgment would have been given between them; and those who were made to inherit the Book after them are most surely in disquieting doubt concerning it.

(42) And most surely it is a knowledge of the hour, therefore have no doubt about it and follow me: this is the right path.

(43) Nay, they are in doubt, they sport.

(44) Say: Allah gives you life, then He makes you die, then will He gather you to the day of resurrection wherein is no doubt, but most people do not know.

(45) And when it was said, Surely the promise of Allah is true and as for the hour, there is no doubt about it, you said: We do not know what the hour is; we do not think (that it will come to pass) save a passing thought, and we are not at all sure.

(46) The believers are only those who believe in Allah and His Apostle then they doubt not and struggle hard with their wealth and their lives in the way of Allah; they are the truthful ones.

(47) Were We then fatigued with the first creation? Yet are they in doubt with regard to a new creation.

(48) Forbidder of good, exceeder of limits, doubter,

(49) They will cry out to them: Were we not with you? They shall say: Yea! but you caused yourselves to fall into temptation, and you waited and doubted, and vain desires deceived you till the threatened punishment of Allah came, while the archdeceiver deceived you about Allah.

(50) And (as for) those of your women who have despaired of menstruation, if you have a doubt, their prescribed time shall be three months, and of those too who have not had their courses; and (as for) the pregnant women, their prescribed time is that they lay down their burden; and whoever is careful of (his duty to) Allah He will make easy for him his affair.