If we follow the Sanskrt we get the cognate jaagarti: https://en.wiktionary.org/wiki/जागर्ति#Sanskrit
Which lists the root as *h₁ger- (“to be awake, to awaken”).
But that root is missing from Wiktionary, which isn't a good sign, but compare:
https://en.wiktionary.org/wiki/Reconstruction:Proto-Indo-Eur...
Although tracing this forward I see the obvious derivatives (vajra, vaaja) and it would be peculiar, but not unheard of, for the word to take two mutations.
I'm basically on a random walk at this point, but here's that missing root again https://en.wiktionary.org/wiki/ἐγείρω#Ancient_Greek and I am once again left wondering...
Exitare! Ok. Nope completely different roots. Someone should really write up *h₁ger- it's pretty important...