IF the key to a word’s meaning is its etymological history and use in the prior centuries, THEN Kittel was ingenious and gold. It fell out of favor with many scholars when the light dawned that a word means what it means not in its history, but in its current use. Synchronic, not diachronic. And that kind of took the wind out of the Kittel sails, fwiw. Dr. Nagel captured this with the saying: “We do not do theology by way of etymology.”
The meaning of a word "in its current use" is limited by the meanings it has had in the past. An example I use is the word "bar." Its meaning requires context. E.g., A member of the bar went into a bar and sat at the bar. The pianist was playing bars of music. "He's the best pianist I've heard, bar none," said the bartender. Just then another man rushed in, "There's a grizzly bar outside, bar the door with that heavy bar."
Even with all those different meanings, "bar," will not mean, "blue" or "bicycle".
The history/origin of a word can also help with different nuances between different words. ἀγαπάω/ἀγάπη, φιλέω/φιλία/φίλος/φίλη, ἐράω/ἔρως can all be translated, "love" (both verbs and nouns), but there can be differences in nuances based on the context; or they could be synonymous. The use of ἀγαπάω and φιλέω in John 21:15-17 are probably synonymous. However, ἀγαπάω is the only word used in the commands for us to love one another, never φιλέω.
The image is two or three overlapping circles. One circle contains the definitions of ἀγαπάω, another the definitions of φιλέω and a third could be the definitions of ἐράω. Some of the definitions overlap. Some do not. (The same image is used of translating a word, e.g., ἀγαπάω and love. Some of our definitions of love overlap the definitions of ἀγαπάω, but there are also uses of these words that are not common to each other; that our outside of the overlapped areas.
One element where Kittel (or detailed word studies can help) is that the use of some Greek words for the Hebrew in the LXX added nuances to the word that weren't present in Classical Greek. The use of κύριος for יהוה added a nuance that wasn't part of the word before. Similarly, the use of εἰρἠνη for שָׁלוֹם added definitions beyond "absence of war."
