insufficient

The word 'insufficient' is a direct borrowing from Latin insufficiens, formed by the negative prefix in- attached to sufficiens, the present participle of sufficere ("to supply, be adequate"). Sufficere itself literally meant "to put under, to supply," from sub- ("under") and facere ("to make, do"). The core logic is that something which "makes under" or "provides the base" is adequate. Therefore, by adding the negative prefix, the term evolved to signify a state of not meeting the required or adequate level, a concept that has remained stable from its Latin origins into modern English usage.

Structure: in (not) + sufficient (enough) - in: Latin origin, a prefix meaning "not". - sufficient: From Latin sufficiens, meaning "adequate, enough". The root is a combination of sub- ("under") + facere ("to make, do").