Abarim Publications' online Biblical Greek Dictionary
The adjective ιδιος (idios) means one's own or private as opposed to public, or peculiar as opposed to normal or general. It comes from the same ancient Proto-Indo-European root as the third person reflexive pronoun (or ος, hos, meaning "he who" or "his") and relates to the word "idiom" which refers to speech typical to a people or place. The singular feminine accusative form of our word often occurs independently of a noun and implies "his own [privacy]" or "privately". Together with καιρος (kairos), meaning time, our adjective forms an idiom meaning "in its own time" or "in due time". The genitive plural may describe one's familiars, one's friends.
In antiquity people still realized that everything that separates humankind from the animals is due to our ability to interact (everything from language and art up to modern technology), and a person who for whatever reason failed to fit into the greater social fabric was deemed inferior to folks that didn't and fit right in.
Our adjective occurs 113 times in the New Testament, see full concordance, and from it in turn derives:
The noun ιδιωτης (idiotes), which literally describes something peculiar, something belonging to a class of its own. This word emphasizes isolation, and may describe a foreign language or perhaps a solitary mountain. It may also describe a sort of human individual, namely the sort that is not connected to the rest of mankind by means of refinery of speech and expression, manners or general knowledge. This sort of person is of course the opposite of the educated elite, and although this division may seem binary or bipolar, it really isn't.
A shared language binds people together as much as shared knowledge does. Great human feats were never accomplished by solitary folks but always by people who were thoroughly integrated into their broader culture. Ignorance and speechlessness don't form schools or companies but turn humanity into clouds of dust. Knowledge and insight form solid buildings.
These things really relate like light and dark, and contrary to common perception: darkness is not the opposite of light but the absence of it. Light is substantial but darkness isn't. Light has a source and a path, but darkness doesn't. Light consists of colors; darkness doesn't. Light contains information; darkness doesn't. Light holds atoms, molecules and objects together, and governs their material economies. Light is the basis of most physical and all chemical processes and manifestations and is even the primary constituent of life. Darkness is the absence of all that. Darkness equals death, destruction, isolation, ignorance and thus idiocy.
Long before anything had had the chance to spoil the perfection of Paradise, the Creator discovered that something within Paradise was not good: It's not good that man is alone (Genesis 2:18).
Our noun is used 5 times; see full concordance.