κἄβλεψε νάπυ, not καὶ βλέπε σινάπυ:

for no Attic writer ever used the form σίναπυ, although there is a reason for each form. For νάπυ may be said, as if it were νάφυ, because it has no φύσις, or growth. For it is ἀφυὲς and little, like the anchovy, which is called ἀφύη, and is called σίναπυ, because it injures the eyes (σίνεται τοὺς ὦπας) by its smell, as the onion has the name of κρόμμυον, because it makes us wink our eyes (ὅτι τὰς κόρας μύομεν). And Xenarchus the comic writer says, in his Scythians—

This evil is no longer evil; so
My daughter is corrupted by the stranger.

And that exquisite writer, Aristophanes, mentions salt and vinegar, saying, in the place where he speaks of Sthenelus the tragedian,—

A. How can I swallow Sthenelus's words?
B. By soaking them in vinegar or white salt.

3. We then, my good friend, have gone along with you in these inquiries. But we have a right to expect an answer from you, in what author the word παροψὶς is used for a vessel. For when speaking of some victuals of various sorts, which were carefully dressed, and of some other things of this sort, I am aware that Plato, in his Festivals, has used the following expressions—

Whence barley-cakes might be got, and παροψίδες.

And again, in his Europa, speaking at considerable length of some exquisite dish, he has used the following expressions among others—

A. The woman is asleep;
B. I am aware
That she is doing nothing.
A. The παροψίδες
Are all awake; and there is not a thing
More calculated to give pleasure always.
B. But where are these παροψίδες, I pray you?

And in the passage immediately following, he uses the word παροψὶς, as if it were equivalent to παροψώνημα, a delicacy; and in his Phaon he says—