هو يحرك قطعة اللعب فقط.

In Arabic, the verb itself already shows the subject. يحرّك means he moves / he is moving, so هو is not strictly necessary.

It is often added for:

• emphasis
• contrast
• clarity

So both are possible:

• هو يحرّك قطعة اللعب فقط
• يحرّك قطعة اللعب فقط

The version with هو can feel a bit more explicit: He moves only the game piece.

يحرك means he moves in the sense of causing something else to move.

That is important: it is a transitive verb, so it takes an object. Here, the object is قطعة اللعب.

So the pattern is:

• هو = he
• يحرك = moves
• قطعة اللعب = the game piece / playing piece

Because the sentence is talking about moving something else, not the subject moving by himself.

• يحرّك = he moves something
• يتحرّك = he moves / he is moving himself

So:

• هو يحرّك قطعة اللعب = He moves the game piece
• هو يتحرّك = He is moving

English uses move for both ideas, but Arabic often distinguishes them clearly.

It can be either, depending on context.

The Arabic imperfect verb can mean:

• he moves
• he is moving
• sometimes even he does move

So هو يحرّك قطعة اللعب فقط could mean:

• He moves only the game piece
• He is moving only the game piece

Context tells you which is intended.

Because قطعة اللعب is the direct object of يحرك.

The basic meaning is:

• He — subject
• moves — verb
• the game piece — object

So the sentence order here is basically:

subject + verb + object

Arabic also very often allows verb-first order, so you may also see:

يحرّك قطعة اللعب فقط

That is also normal Arabic.

It is an iḍāfa construction, often called a construct phrase.

That means:

• قطعة = piece
• اللعب = play / game-related noun, depending on context

Together, they form a unit meaning something like:

• the game piece
• the playing piece
• literally, piece of play

In an iḍāfa:

• the first noun comes first
• the second noun defines or specifies it
• the whole phrase acts like one noun phrase

That is a normal rule of iḍāfa.

In an iḍāfa, the first noun usually does not take ال, and the second noun can carry the definiteness.

So:

• قطعة اللعب = the game piece
• not usually القطعة اللعب in this structure

Because the second noun is definite, the whole phrase becomes definite.

Here فقط means only / just, and because it comes after قطعة اللعب, it most naturally limits that phrase.

So the sentence means:

• He moves only the game piece

In other words, only applies to the game piece, not to he.

Compare:

• هو فقط يحرّك قطعة اللعب = Only he moves the game piece
• هو يحرّك قطعة اللعب فقط = He moves only the game piece

So word placement changes the emphasis.

If you show the case endings, it would be read approximately as:

هو يحرّك قطعةَ اللعبِ فقط

The important parts are:

• يحرّكُ — verb in the indicative
• قطعةَ — direct object, so it is in the accusative
• اللعبِ — second term of the iḍāfa, so it is in the genitive

In normal unvowelled writing, these endings are usually not written, but they are still understood grammatically.

It is grammatically understandable as an iḍāfa, but learners should know that the most natural expression can depend on context.

You may also encounter words based on اللعبة, which often means game or toy. In some contexts, a phrase like قطعة اللُّعبة may sound more natural for a piece belonging to a game.

So the sentence as written is useful grammatically, but in real usage, the exact noun choice may vary depending on whether you mean:

• a board-game piece
• a toy part
• a puzzle piece
• a playing piece in a specific game

Yes. A very common alternative is لا ... إلا.

So you could also say:

هو لا يحرّك إلا قطعةَ اللعب

That also means:

He moves only the game piece

Both patterns are common:

• ... فقط
• لا ... إلا

The فقط version is shorter and very common in both written and spoken-style Modern Standard Arabic.

Yes. Arabic very often uses verb-first order, so this is also natural:

يحرّك قطعة اللعب فقط

That version still means He moves only the game piece.

Adding هو at the beginning is not wrong; it just makes the subject more explicit. A learner will often see both styles.