What is "moun pa"

Moun pa → favorite person, close friend, pal, bosom buddy

He's my buddy.
Se moun pa mwen.(non-contracted)
Se moun pa m. (contracted)
Watch for contractions.  And do not confuse this "pa" with the negative indicator "pa" : )

-Do you know this lady?
  Eske ou konnen madanm sa a?

-Yes I know her.  She's a close friend.
  Wi mwen konnen l. Li se moun pa m.

-If I knew she was your pal I would have been nice to her.
  Si m te konnen li te moun pa w, mwen ta byen aji avè l.

Moun pa is an expression that could mean favoritism.
Ou nan moun pa.
You're playing favorite.

Moun pa se dra.
Good friends are like sheets. (Good friends are a shelter)

He would not have gotten the job if he didn't have someone on the inside.
Li pa ta jwenn travay la si li pa't gen moun pa anndan an.

You must have someone on the inside to get ahead in this country.
Fòk ou gen moun pa pou w avanse nan peyi sa.

See some other Haitian Creole words for "favoritism"

Paspouki in Creole is?

Paspouki → unfairness, favoritism, discrimination

Example:
You're playing favorite.
W'ap fè paspouki.
Ou nan paspouki.

I don't play favorites!
Mwen pa nan paspouki!

The teacher is discriminating against his students.
Pwofesè a nan paspouki avèk elèv li yo.

Other Creole synonyms for paspouki are: patipri, pasyalite, balans panche, moun pa