A lapsus is an involuntary mistake made while writing or speaking. According to Freud

Sigmund Freud

Sigmund Freud , born Sigismund Schlomo Freud , was an Austrian neurologist who founded the discipline of psychoanalysis...

's early psychoanalytic theory

Psychoanalytic theory

Psychoanalytic theory refers to the definition and dynamics of personality development which underlie and guide psychoanalytic and psychodynamic psychotherapy. First laid out by Sigmund Freud, psychoanalytic theory has undergone many refinements since his work...

, a lapsus represents a missed deed that hides an unconscious

Unconscious mind

The unconscious mind is a term coined by the 18th century German romantic philosopher Friedrich Schelling and later introduced into English by the poet and essayist Samuel Taylor Coleridge...

 desire.

In literature there are a number of different lapsus depending on the mode of correspondence:

• lapsus linguae (pl. same): slip of the tongue.
• lapsus calami: slip of the pen. With the variation of lapsus clavis: slip of the typewriting
• lapsus manus: slip of the hand. Similar to lapsus calami.
• lapsus memoriae: slip of memory.

Types of slips of the tongue

Slips of the tongue can happen on any level:

• Syntactic
  Syntaxis
  Syntaxis is style in writing or in rhetoric that favors complex syntax, as against simple sentence structures. For example, 19th-century German academic prose, and John Milton's "Paradise Lost" poetry in English are notably syntactic....
  
   - is instead of was.
• Phrasal slips of tongue - I'll explain this tornado later.
• Lexical/semantic - moon full instead of full moon.
• Morphological
  Morphology (linguistics)
  In linguistics, morphology is the identification, analysis and description, in a language, of the structure of morphemes and other linguistic units, such as words, affixes, parts of speech, intonation/stress, or implied context...
  
   level - workings paper
• Phonological (sound slips) - flow snurries instead of snow flurries

Additionally, each of these five levels of error may take various forms:

• Anticipation
  Anticipation
  Anticipation can refer to:* Anticipation , a 1971 album by Carly Simon* Anticipation , the title track of this album* Anticipation , a 2008 comedy album by Lewis Black*Anticipation...
  
  s: Where an early output item is corrupted by an element belonging to a later one. Thus "reading list" - "leading list".
• Perseverations: Where a later output item is corrupted by an element belonging to an earlier one. Thus "waking rabbits" - "waking wabbits".
• Deletions: Where an output element is somehow totally lost. Thus "same state" - "same sate".
• Shift: Moving a letter. Thus "black foxes" - "back floxes".
• Haplologies: half one word and half the other. Thus "stummy" instead of "stomach or tummy". (Smith, 2003)
• Pun
  Pun
  The pun, also called paronomasia, is a form of word play which suggests two or more meanings, by exploiting multiple meanings of words, or of similar-sounding words, for an intended humorous or rhetorical effect. These ambiguities can arise from the intentional use and abuse of homophonic,...