【Error】 , 【mistake】 ,  【blunder】 ,  【slip】 ,  【lapse】 ,  【faux pas】 ,  【bull】 ,  【howler】 ,  【boner】  are comparable when they denote something (as an act, statement, or belief) that involves a departure from what is, or what is generally held to be, true, right, or proper.

【Error】  implies a straying from a proper course and suggests such guilt as may lie in failure to take proper advantage of a guide (as a record or manuscript, a rule or set of rules, or a principle, law, or code); thus, a typographical  【error】  results when a compositor misreads a manuscript; an  【error】  in addition involves some failure to follow the rules for addition; an  【error】 in conduct is an infraction of an accepted code of manners or morals.

【Mistake】  implies misconception, misunderstanding, a wrong but not always blameworthy judgment, or inadvertence; it expresses less severe criticism than  【error】 .

【Blunder】  is harsher than  【mistake】  or  【error】 ; it commonly implies ignorance or stupidity, sometimes blameworthiness.

【Slip】  carries a stronger implication of inadvertence or accident than  【mistake】 and often, in addition, connotes triviality. Often, especially when it implies a transgression against morality, the word is used euphemistically or ironically.

【Lapse】 , though sometimes used interchangeably with  【slip】 , stresses forgetfulness, weakness, or inattention more than accident; thus, one says a  【lapse】  of memory or a  【slip】 of the pen, but not vice versa.

When used in reference to a moral transgression, it carries a weaker implication of triviality than  【slip】 and a stronger one of a fall from grace or from one’s own standards.

【Faux pas】 is most frequently applied to a 【mistake】 in etiquette.

【Bull】 ,  【howler】 , and  【boner】  all three are rather informal terms applicable to blunders (and especially to blunders in speech or writing) that typically have an amusing aspect.

A  【bull】 may be a grotesque 【blunder】 in language typically characterized by some risible incongruity or it may be a mere stupid or gauche 【blunder】 .

A 【howler】 is a gross or ludicrous 【error】 based on ignorance or confusion of ideas; the term is used especially of laughable errors in scholastic recitations or examinations.

A  【boner】  may be a grammatical, logical, or factual 【blunder】 in a piece of writing that is usually so extreme as to be funny <a few historical boners … such as dinosaurs surviving until medieval times —Coulton Waugh >  or it may be a ridiculous or embarrassing 【slip】 of the kind that results from a sudden 【lapse】 (as of attention or from tact or decorum).