We often use the words "grease" or "greasy" for the presence of a slippery or oily substance, especially in food:
Fast food has a lot of grease in it.
Fried chicken is greasy.
The word "greasy" is an adjective:
It’s not a good idea to eat a lot of greasy food because it contains so much unhealthy fat.
The pizza we ate last night was good, but it was a little greasy.
Tom likes greasy food, like hamburgers and french fries.
The kitchen at the diner is all greasy because of the deep-frying that they do there. (A diner is a small restaurant that specializes in fast food.)
A hamburger and french fries may taste good, but sometimes this popular food combination is a little too greasy.
Grease is a lubricating substance that reduces friction between moving parts.
A mechanic gets a lot of grease on his hands while working on cars.
The wheel stopped squeaking after a little grease was applied to it.
After working on his car all day, he has some grease on his face.
It’s the squeaky wheel that gets the grease. (This an expression. It means that a person who complains loudly enough will get more attention paid to his or her problem.)
