Ангоб красный.

In Russian, the verb to be is usually omitted in the present tense.

So:

• Ангоб красный = The engobe is red

Literally, Russian often just says [noun] + [adjective] in this kind of sentence.

Compare:

• Дом большой = The house is big
• Чай горячий = The tea is hot
• Ангоб красный = The engobe is red

If you wanted past or future, Russian would use forms of быть:

• Ангоб был красный = The engobe was red
• Ангоб будет красный = The engobe will be red

Красный is the masculine singular nominative form of the adjective red.

It matches ангоб, which is a masculine singular noun. In Russian, adjectives must agree with the noun they describe in:

• gender
• number
• case

So you get:

• masculine: красный
• feminine: красная
• neuter: красное
• plural: красные

Because ангоб is masculine singular, красный is the correct form.

A very common clue in Russian is the word ending.

Nouns ending in a hard consonant are often masculine.
Ангоб ends in -б, so it is treated as masculine.

That is why you say:

• ангоб красный
• not ангоб красная
• not ангоб красное

This is a very useful pattern for learners, although there are some exceptions elsewhere in Russian.

It is an adjective, but in this sentence it is used as a predicate adjective.

That means it is not directly attached inside a noun phrase like:

• красный ангоб = red engobe

Instead, it is the part that tells us something about the subject:

• Ангоб красный = The engobe is red

So both words are in the nominative, but their roles are different:

• ангоб = subject
• красный = predicate adjective

The difference is mainly grammatical function.

• Красный ангоб = red engobe
  This is a noun phrase: an adjective directly modifying a noun.

• Ангоб красный = The engobe is red
  This is a full sentence: the noun is the subject, and the adjective is the predicate.

So:

• Красный ангоб лежит на столе = The red engobe is lying on the table
• Ангоб красный = The engobe is red

Russian can sometimes change word order for emphasis, but these two structures are still different in meaning and function.

Yes, Russian word order is fairly flexible, but the most neutral version here is:

• Ангоб красный

You might also see:

• Красный ангоб — but this usually means red engobe, not the engobe is red
• Красный ангоб? or Ангоб-то красный in special contexts with emphasis or contrast

For a beginner, it is best to learn:

• noun + adjective for X is red
• adjective + noun for red X

That rule will help in many simple sentences.

It is pronounced roughly like KRAS-nyy, but the exact Russian sound is a bit different from English.

A simple learner-friendly breakdown:

• крас- sounds like kras
• -ный sounds approximately like -nyy

A few notes:

• The р is a rolled or tapped r
• The сн cluster is pronounced clearly
• The final -ый is not exactly an English sound; learners often approximate it as -y or -iy

So красный is often approximated as:

• KRAHS-nihy or KRAS-ny

Depending on your textbook/transliteration system, you may see different spellings, but the important point is that it is the standard masculine form.

Because this is a simple present-tense statement with a subject and a predicate adjective.

• Ангоб is the subject, so nominative makes sense.
• красный is a predicate adjective, and in this kind of sentence it is also normally in the nominative.

So Russian says, in effect:

• [subject in nominative] + [adjective in nominative]

Examples:

• Суп горячий = The soup is hot
• Урок трудный = The lesson is difficult
• Ангоб красный = The engobe is red

In modern everyday Russian, красный is the normal choice.

The short-form adjective красен exists, but it sounds:

• literary
• poetic
• old-fashioned
• stylistically marked

So for normal speech and standard learning purposes, use:

• Ангоб красный

not:

• Ангоб красен

Short-form adjectives do exist in Russian, but they are not used equally with all adjectives in all situations, and they are not usually the first form a beginner should use here.

Yes, absolutely. It is a complete and natural sentence.

Russian often allows very short present-tense sentences like this:

• Снег белый = Snow is white
• Небо синее = The sky is blue
• Ангоб красный = The engobe is red

Even without a separate word for is, the sentence is grammatically complete.