What does ἤγγικεν mean? Well the κεν is looks like a perfect third person singular ending. The η at the beginning could be vocalic reduplication of some sort. The verb itself could be γινωσκοω.
The Analytical lexicon says perfect, active, indicative, 3rd person singular of ὲγγιζω “I come near”, v-2a(1). So I was right in everything except it’s not from γινωσκοω. But where did the ζ go?
The Morphology of Biblical Greek (MBG) says v2 verbs form their present tense stem by adding a consonantal iota ι.
BBG (Basics of Biblical Greek) also says ι was added to roots ending in a stop to form their present stem and the stop + consonantal iota became ιζω (*βαπριδ + ι > βαπτιζω). It was also added to some roots ending in a consonant resulting in a doubling of the consonant ie (**βαλ+ι>βαλλω) and added to other roots were it became an iota and moved somewhere else in the word (*ἀρ+ι > ἀρι > αἴρω). This change is called “metathesis”.
So, is the root of the word something like *εγγ? In which case were does the ι come from in ἤγγικεν. MBG lists the future, aorist active and perfect active as ἐγγιῶ, ἤγγισα, and ἤγγικα but gives no explanation for the iotas. The note to 43.7b on attic futures says “Remember, ιζω verbs really have stems ending in a dental.” I hadn’t forgotten but going back to 43.6 a bracketed note says “The original δ or γ reappears in the other tenses, only to be modified for other reasons.”. ie *βαπτιδ + ι + ω > βαπτιζω in the present, and *βαπτιδ + σ + ω > βαπτισσω > βαπτισω in the future. That’s something to watch out for. Oh, maybe the root of ἤγγικεν is really something like *εγγιδ. That would make more sense. Yes that must be it. *εγγιδ > (add case ending) ὲγγιδκεν > (loose the δ) ὲγγικεν. Not sure why the delta drops out though.
Mounce stresses the importance of learning verbal root, which he gives for his vocabulary but I wonder if there is a list somewhere of all verbal roots for all NT words? You would think the analytical lexicon or MBG would give them, although MBG does give tricky ones as footnotes.