Abarim Publications' online Biblical Greek Dictionary
The verb καυχαομαι (kauchaomai) means to enthusiastically, confidently or emphatically declare. It derives from the otherwise unused noun αυχην (auchen), which means neck or throat, not only of humans and animals but also of sea straits and narrow passages in rivers, where the currents are strongest. The idiomatic phrase "to make one's neck to stand" was used to mean "to be high spirited", and a neck that was kept too high (on account of one's great wealth and subsequent pride) could even challenge a ruler's demand for humble subjection.
The derived verb αυχεω (aucheo), to "neck", subsequently means to loudly and confidently declare. Our verb καυχαομαι (kauchaomai) was possibly formed by merit of the suffix εκ (ek), out of, to form a verb — to "ex-neck-ize" — that describes the rushing of whatever medium through a narrowed canal, but specifically the forcible declaration of confidence: to speak loudly, to vent one's certainties on the authority of the volume of one's voice.
The subtleties of our verb are compound, also because certainty is a futile virtue when the thing so confidently expressed may, upon close examination, turn out to be false. Particularly children shout because their lack of depth entices them to confuse every little irritation with the eternal order of the cosmos. More mature people don't shout, but rather invest their confidence in an order that exists independently of their understanding of it, and lean instead of on their own knowledge upon the discourse enjoyed with others of mature mind, knowing that the Creator is never known by any lone ranger but always by a congregation that generously forgives and eagerly learns.
Modern English doesn't really have a proper equivalent of our verb since "boasting" is commonly associated with praise of what one has done, whereas καυχαομαι (kauchaomai) mostly emphasizes what one knows (whether valid or not). It stems from a time when thought about thought was new, when the principles, function and even purpose of systematic and logic contemplation were not widely understood, when the scientific method didn't have the authority it has today, and a statement was validated by one's own heated affirmations rather than by calm demonstration or even the consensus of insightful men. Apparently, such immature practices were still common in Corinth as more than half of the occurrences of our verb in the New Testament are in Paul's letters to the Corinthians (2 Corinthians 11:18).
Paul warned that when everybody is shouting their own convictions, shouting the truth is a foolish thing to do, also since the validity of one's knowledge is really only affirmed by others (1 Corinthians 11:6, 2 Corinthians 12:6). Where verbal cacophony was the standard, loud affirmation was necessary but still worthless (2 Corinthians 12:1), and if he was indeed forced to shout along with the rest of them, he would do so solely to demonstrate his weakness (2 Corinthians 11:30, 12:5).
Our verb is used 38 times in the New Testament, see full concordance, and from it derive:
- Together with the preposition κατα (kata), meaning down from, down upon: the verb κατακαυχαομαι (katakauchaomai), meaning to shout down, to loudly declare with the intend or effect to depreciate or derogate. This ugly verb occurs 4 times in three verses: see full concordance.
- The noun καυχημα (kauchema), which describes an instance, specific result or object of an act of the parent verb: a loud affirming, either a loud declaring of confidence, a boasting, a thing so boasted about, or even its perceived boast-worthiness. This noun occurs 11 times; see full concordance.
- The noun καυχησις (kauchesis), which describes the act, general result or process of boasting: a loud affirmation. This noun occurs 12 times; see full concordance.