deep fryer vs deep fat fryer

deep fryer and deep fat fryer both are nouns.

Word	Noun	Adjective	Verb	Adverb
deep fryer	Yes	No	No	No
deep fat fryer	Yes	No	No	No

As nouns, deep fryer and deep fat fryer are synonyms defined as:

deep fryer and deep fat fryer: A kitchen appliance for deep frying; its size depends on intended use.

Other synonyms of deep fryer include frier, fryer, fryolator.

deep fryer (noun)	deep fat fryer (noun)
A kitchen appliance for deep frying; its size depends on intended use.	A kitchen appliance for deep frying; its size depends on intended use.