Solecism - solipsism

The two nouns solecism and solipsism have distinct meanings, but as they are near homophones (virtually identical in hurried or careless speech), and can both be used to mean 'bad behaviour', they can be confused.

• A solecism (the first vowel is that of 'got', and is stressed; IPA: /ˈsɒl ə sɪs^əm/) was originally
  • "An impropriety or irregularity in speech or diction; a violation of the rules of grammar or syntax; properly, a faulty concord [= Agreement in grammar]" (OED; AWE's emphasis). (The original solecisms were those errors in Greek made by the colonists of Soloi, in Cilicia, nowadays Mersin, in Southern Turkey.) From this, the meaning was extended to
  • "A breach or violation of good manners or etiquette; a blunder or impropriety in manners, etc" (ib).

The general idea of a solecism is 'the sort of error or mistake that causes observers to look down on the perpetrator'; 'a piece of misbehaviour [or grammar] that marks the person responsible as not belonging [or not fit to belong] to the group in whose presence it was made'. (The etymological explanation no doubt includes an element of feeling in Athens, the mother-city, that the colonists of Soloi 'talked like country bumpkins', and 'were not one of us'.)

• Solipsism (pronounced like solecism - except in the second syllable: IPA: /ˈsɒl ɪp sɪs^əm/) is, properly, a philosophical belief. It is "The view or theory that self is the only object of real knowledge or the only thing really existent" (OED, which also equates it with egoism, "The belief, on the part of an individual, that there is no proof that anything exists but his own mind"). It is increasingly being used more loosely and less technically as
  • 'self-centred behaviour', 'selfishness'. It is particularly used of a speaker or writer who always returns to his own personal experience, whatever the apparent topic of discourse. In this sense, solipsism is felt to be bad manners - amounting to solecistic behaviour.

But do not use either word when you mean the other, however similar they are in meaning and area.