This is the 7th most frequent Dutch word.
niet
"Niet" means "not" in English.
'Niet' is used to negate the adjective 'moe' in this sentence, indicating a state contrary to tiredness.
Ik ben niet moe.
I am not tired.
'Niet' negates the verb 'wil' here, expressing unwillingness to eat.
Hij wil niet eten.
He does not want to eat.
'Niet' is employed to negate the entire statement about an action performed during weekends.