The word(s) "fail" appears 18 time(s) in 18 verse(s) in Quran in Mohsin Khan translation.

(11) And (all) faces shall be humbled before (Allah), Al-Hayyul-Qayyum (the Ever Living, the One Who sustains and protects all that exists). And he who carried (a burden of) wrongdoing (i.e. he who disbelieved in Allah, ascribed partners to Him, and did deeds of His disobedience), will be indeed a complete failure (on that Day).

(12) And they ask you to hasten on the torment! And Allah fails not His Promise. And verily, a day with your Lord is as a thousand years of what you reckon.

(13) (It is) a Promise of Allah (i.e. Allah will give victory to the Romans against the Persians), and Allah fails not in His Promise, but most of men know not.

(14) Did we take them as an object of mockery, or have (our) eyes failed to perceive them?"

(15) But those who fear their Lord (Allah) and keep their duty to Him, for them are built lofty rooms, one above another under which rivers flow (i.e. Paradise). (This is) the Promise of Allah: and Allah does not fail in (His) Promise.

(16) In order that you may not grieve at the things that you fail to get, nor rejoice over that which has been given to you. And Allah likes not prideful boasters.

(17) The likeness of those who were entrusted with the (obligation of the) Taurat (Torah) (i.e. to obey its commandments and to practise its laws), but who subsequently failed in those (obligations), is as the likeness of a donkey which carries huge burdens of books (but understands nothing from them). How bad is the example of people who deny the Ayat (proofs, evidence, verses, signs, revelations) of Allah. And Allah guides not the people who are Zalimun (polytheists, wrong-doers, disbelievers).

(18) And indeed he fails who corrupts his ownself (i.e. disobeys what Allah has ordered by rejecting the true Faith of Islamic Monotheism or by following polytheism or by doing every kind of evil wicked deeds).