efferent neuron vs nerve cell

efferent neuron and nerve cell both are nouns.

Word	Noun	Adjective	Verb	Adverb
efferent neuron	Yes	No	No	No
nerve cell	Yes	No	No	No

As nouns, nerve cell is a hypernym of efferent neuron; that is, nerve cell is a word with a broader meaning than efferent neuron:

efferent neuron: a neuron conducting impulses outwards from the brain or spinal cord
nerve cell: a cell that is specialized to conduct nerve impulses

Other hypernyms of efferent neuron include neuron.

efferent neuron (noun)	nerve cell (noun)
a neuron conducting impulses outwards from the brain or spinal cord	a cell that is specialized to conduct nerve impulses