Illicitator licitatur, sed emptor non licitatur.

Because licitatur comes from a deponent verb.

In Latin, deponent verbs:

• have passive-looking forms
• but an active meaning

So licitatur looks like a passive form, but it means he/she bids or is bidding, not is bidden.

This is one of the first things English speakers notice, because English does not really have a direct equivalent.

The dictionary form is licitor, licitari, licitatus sum.

That tells you it is:

• a 1st-conjugation deponent verb
• with principal parts that include passive-looking forms

From that verb:

• licitor = I bid
• licitaris = you bid
• licitatur = he/she bids

So the form in the sentence is exactly what you would expect from a deponent verb.

Licitatur is:

• 3rd person singular
• present indicative

So it means:

• he bids
• she bids
• is bidding

Latin often leaves the subject pronoun unstated, because the verb ending already tells you the person and number.

They are in the nominative singular, the case normally used for the subject of a finite verb.

In this sentence:

• Illicitator is the subject of the first licitatur
• emptor is the subject of the second licitatur

A Latin learner from English often expects word order to show the subject, but Latin usually shows it through case endings instead.

Latin usually does not need to state subject pronouns unless they are being emphasized.

The ending -tur already tells you that the verb is:

• 3rd person
• singular

So licitatur by itself already means he/she bids.

If Latin wanted extra emphasis, it could add a pronoun, but normally that is unnecessary.

Because non normally negates the verb or the whole predicate.

So:

• non licitatur = does not bid / is not bidding

This is a very common Latin pattern:

• non
  • verb

Here it clearly contrasts the second clause with the first:

• one person bids
• the other does not

Sed means but.

It joins the two clauses and marks a contrast:

• first clause: one subject performs the action
• second clause: the other subject does not

So sed is a straightforward coordinating conjunction here.

They are similar in function here, but they are not from the same pattern in exactly the same way.

Both are:

• masculine
• singular
• used as subjects

And both are typically treated as 3rd-declension nouns:

• licitator, licitatoris
• emptor, emptoris

A learner may first think -or always behaves like a 2nd-declension masculine noun, but here it does not. These are 3rd declension nouns.

Yes, they are closely related in formation and meaning.

• licitator is an agent noun: the one who bids
• licitatur is the verb: bids

Latin very often forms nouns and verbs from the same root, and that is what you are seeing here.

This is helpful for vocabulary building: once you know the verb, related nouns often become easier to recognize.

Yes. Latin word order is much more flexible than English word order.

This sentence could be rearranged in various ways without changing the basic grammar, because the forms already show what each word is doing.

However, the given order is neat and clear:

• subject + verb
• sed
• subject + non
  • verb

That makes the contrast especially easy to follow.

Not in this sentence.

The verb is used here without a direct object, so the sense is simply that someone bids. Latin can do this just as English can say The bidder bids without naming the exact thing bid on.

So the sentence is grammatically complete as it stands.

A learner might wonder about that, because many would expect licitator.

If your text really has Illicitator, it is worth checking:

• whether that spelling is intentional in your source
• whether it is a textual or editorial variation
• whether it may simply be a typo

Regardless, in this sentence it is functioning grammatically as the subject noun of the first clause, parallel to emptor in the second.