Смысл этого слова кажется неясным.

Because смысл is the grammatical subject of the sentence.

• смысл = meaning
• It is the thing that seems unclear

So the structure is basically:

• Смысл ... кажется неясным
• The meaning ... seems unclear

That is why смысл is nominative singular.

Because Russian uses the genitive to express of relationships.

• слово = word
• смысл слова = the meaning of the word

So:

• этого слова = of this word

More literally, the phrase breaks down like this:

• смысл = meaning
• этого слова = of this word

This is very common in Russian:

• цвет машины = the color of the car
• начало фильма = the beginning of the film
• смысл слова = the meaning of the word

Because after казаться (to seem), the describing word is very often put in the instrumental case.

So in:

• Смысл этого слова кажется неясным

the adjective неясный becomes instrumental singular masculine:

• неясный → неясным

This is a common pattern:

• Он кажется усталым = He seems tired
• Она кажется счастливой = She seems happy
• Это кажется странным = This seems strange

So here:

• смысл is masculine singular
• therefore неясным also has masculine singular agreement, but in the instrumental case

Because неясный is the nominative form, but казаться usually requires the complement in the instrumental.

Compare:

• Смысл неясный = The meaning is unclear / an unclear meaning
  This sounds incomplete or like a label, not the best normal sentence.
• Смысл кажется неясным = The meaning seems unclear

So the instrumental here is triggered by кажется.

Кажется is the 3rd person singular present-tense form of казаться, which means to seem.

So:

• кажется = seems

It matches смысл, which is singular:

• Смысл кажется... = The meaning seems...

If the subject were plural, you would use:

• кажутся

For example:

• Эти слова кажутся странными = These words seem strange

Because the dictionary form is казаться, not казать.

The ending -ся often makes learners think of a literal reflexive meaning, but in many verbs it is simply part of the verb’s normal form. In this case:

• казаться = to seem

You should learn it as a whole verb.

So кажется does not mean something like shows itself in normal usage. It simply means seems.

Yes. That is a very natural alternative.

• Смысл этого слова неясен = The meaning of this word is unclear
• Смысл этого слова кажется неясным = The meaning of this word seems unclear

The difference is:

• неясен states it more directly
• кажется неясным sounds softer or less absolute, like it appears unclear or it seems unclear

So the version with кажется is a little more cautious.

Because неясный is a standard adjective meaning unclear, and in this case it is written as one word.

So:

• ясный = clear
• неясный = unclear

In the sentence, that adjective is in instrumental form:

• неясный → неясным

Russian often writes не together with adjectives when the result is a normal opposite word.

Because adjectives in Russian agree with the noun they describe in gender, number, and case.

Here:

• смысл = masculine singular
• the adjective describing it must also be masculine singular

Because the construction with кажется calls for the instrumental, you get:

• masculine singular instrumental = неясным

So the adjective agrees with смысл, not with слова.

No, Russian word order is flexible.

The neutral order is:

• Смысл этого слова кажется неясным.

But other orders are possible for emphasis, for example:

• Неясным кажется смысл этого слова.
• Смысл кажется неясным.

The standard version is best for learners, because it is the clearest and most neutral.

In forms like этого, ого, and его, the letter г is usually pronounced like v.

So этого is pronounced approximately:

• этава

not этога

This is a very common pronunciation pattern in Russian grammar, especially in adjective and pronoun endings.

So although it is written:

• этого

it sounds roughly like:

• этава

Often yes, but the nuance can change slightly.

• значение слова usually means the meaning of a word in a dictionary or lexical sense
• смысл слова can sound a bit broader, like sense, meaning, or what the word conveys

In many contexts they are close, but значение слова is especially common when talking about vocabulary and definitions.

So:

• Значение этого слова кажется неясным is also possible and natural.

Yes. Russian кажется can be used both:

1. with a subject:

   • Смысл этого слова кажется неясным = The meaning of this word seems unclear

2. impersonally:

   • Мне кажется, что смысл этого слова неясен = It seems to me that the meaning of this word is unclear

That second pattern is extremely common in Russian conversation.

So learners often meet both:

• X кажется Y-ом / Y-ым
• Мне кажется, что...