This is the 3068th most frequent French word.
nuls
"Poor," "useless," or "without talent."
In this sentence, "nuls" is used as an adjective to describe "jeux" (games) as being bad or of poor quality.
Ces jeux sont vraiment nuls.
These games are really bad.
Here, "nuls" is used to describe someone’s lack of skill or proficiency in mathematics.
Ils sont nuls en mathématiques.
They are bad at mathematics.
In this case, "nuls" implies that the efforts were ineffective or useless.