Benoni is the word you would use in Israel to ask for a medium-sized cup of coffee. The word connotes something medium, or average. It comes from the proposition bein, meaning in between.
The benoni plays a central role in Jewish ethical literature. He or she is the average person, neither completely righteous nor completely wicked, who has to struggle to try to be better. Maimonides famously defines the benoni as one whose merits and faults are equal. Therefore everyone should see themselves as a benoni at all times; one good deed can tip the balance.
The founder of Chabad Chasidism, Rabbi Schneur Zalman of Liady, subtitled his classic work Tanya, Sefer Shel Benonim, The Book of the In-between. Impelled by the talmudic statement of the sage Rabba, "I, for example, am a benoni," Rabbi Shneur Zalman adopts a more exacting definition of the benoni.
If someone as great as Rabba is a benoni, then clearly we need to raise the bar. The Tanya defines a benoni as one who never sins, but nevertheless has stirrings towards sin in his heart that he overcomes.
This is the characterisation of the benoni in the sense that it is a level to which, according to Rabbi Shneur Zalman, we can all realistically aspire.