blunder

/ˈblən-dər/

Middle English blundren, probably of Scandinavian origin; akin to Old Norse blunda to shut one's eyes, doze, Norwegian dialect blundra

verb

  1. to move unsteadily or confusedly

  2. to make a mistake through stupidity, ignorance, or carelessness

  3. to utter stupidly, confusedly, or thoughtlessly

In their exhaustion they often blundered against each other …

noun

  1. a gross error or mistake resulting usually from stupidity, ignorance, or carelessness

a costly tactical blunder

error mistake blunder slip lapse mean a departure from what is true, right, or proper. error suggests the existence of a standard or guide and a straying from the right course through failure to make effective use of this. mistake implies misconception or inadvertence and usually expresses less criticism than error.