"Egrommi idakosi."

Translation: They attack with knives.

[SprightBark]

So we have had ohīlvossi and egrommi as with (the) knives. I was curious what the difference was, so I thought I would look up the definitions at https://wiki.dothraki.org/High_Valyrian_Vocabulary

egros ['egros]
n. 3sol. edge; blade; sword (cf. egry.)

egry ['egry]
n. 2lun. knife, razor (cf. egros.)
Vala egromy rōbir ezīmza. — The man splits the fig with a knife.

ohīlagon [oˈhiːlagon]
v. C-fin. to stab (poss. oz- + hīlagon.)

ohīlvos [o'hiːlvos]
n. 3sol. dagger, knife ( < ohīlagon + -vos.)
Azantys ohīlvoso taobe idakos! — The knight is attacking the boy with a dagger!

So egry (knife, razor) is related to egros (blade, edge), whereas ohīlvos (dagger, knife) is related to ohīlagon (to stab).