This is the 13899th most frequent German word.
fetten
To grease or oil.
Here, 'fettet' is a verb meaning 'to lubricate', pertaining to maintaining smooth operation.
Er fettet das Kettenschloss, um es geschmeidig zu halten.
He lubricates the chain lock to keep it smooth.
Here, 'fette' is used as a verb meaning 'to grease', referring to the action of applying oil or fat.
Ich fette die Pfanne vor dem Braten.
I grease the pan before frying.
In this sentence, 'fetten' is used as an adjective to describe something as being greasy or slippery.