This is the 557th most frequent Vietnamese word.
hợp
"Suitable" or "to combine."
In this sentence, 'hợp' means 'to be compatible with' or 'to get along well with' depending on the context.
Bộ đôi này rất hợp nhau.
This duo gets along well.
Here, 'hợp' means 'to suit' or 'to be suitable for' something.
Màu xanh hợp với bạn.
Blue suits you.
In this case, 'hợp' is part of the compound word 'hợp tác', meaning 'to collaborate' or 'to cooperate'.