בחידה מופיע צופן.

It is made of two parts:

• ב־ = in
• חידה = riddle / puzzle

So בחידה means in a riddle or in the riddle, depending on context.

In unpointed Hebrew, it can be either.

• בְּחִידָה = in a riddle
• בַּחִידָה = in the riddle

Both are normally written the same way: בחידה.

So if you are reading ordinary Hebrew without vowel marks, the context tells you whether it is definite or indefinite.

Because Hebrew has no indefinite article. There is no separate word for a / an.

So:

• צופן can mean a cipher / a code
• הצופן means the cipher / the code

That is why Hebrew learners often feel that something is “missing,” but it is completely normal Hebrew.

Here, מופיע is the present-tense form of the verb להופיע.

In this sentence it means something like:

• appears
• shows up
• occurs
• sometimes is found

So מופיע צופן is essentially a cipher appears or a cipher is found.

Because it agrees with צופן, which is a masculine singular noun.

Hebrew present-tense verb forms agree in gender and number with the subject.

• צופן מופיע = a masculine singular cipher appears
• If the noun were feminine, you would expect מופיעה
• If it were plural, you would expect מופיעים or מופיעות

Even though צופן comes after מופיע in this sentence, it is still the subject, so the agreement is with צופן.

That is a very common question. In Hebrew, the present tense often uses forms that look adjective-like, because historically they are participles.

So מופיע can behave somewhat like an adjective in form, but in this sentence it functions as the verb: appears.

This is normal for Hebrew present tense.

The dictionary form is להופיע.

That verb can mean:

• to appear
• to show up
• to be displayed
• in some contexts, to perform or to appear on stage

In this sentence, the meaning is clearly the appear / occur / be found sense.

Hebrew word order is more flexible than English word order.

A more neutral order would often be:

• צופן מופיע בחידה

But בחידה מופיע צופן puts the focus first on the setting: in the riddle.

That fronting can sound a little more literary, descriptive, or context-focused. It is still perfectly understandable Hebrew.

It can mean either, depending on context.

Common translations include:

• cipher
• code
• encoding

If the meaning has already been given to you, follow that context. In a puzzle or riddle sentence, cipher is often a very natural translation.

A simple pronunciation guide is:

bechidá mofi'a tzófen

If the first word is meant as in the riddle rather than in a riddle, the first part may sound more like:

bachidá

So the unpointed spelling בחידה does not show that difference, but the pronunciation does.