fairlead vs pulley

fairlead and pulley both are nouns.

Word	Noun	Adjective	Verb	Adverb
fairlead	Yes	No	No	No
pulley	Yes	No	No	No

As nouns, pulley is a hypernym of fairlead; that is, pulley is a word with a broader meaning than fairlead:

fairlead: a pulley-block used to guide a rope forming part of a ship's rigging to avoid chafing
pulley: a simple machine consisting of a wheel with a groove in which a rope can run to change the direction or point of application of a force applied to the rope

Other hypernyms of fairlead include block, pulley-block, pulley block.

fairlead (noun)	pulley (noun)
a pulley-block used to guide a rope forming part of a ship's rigging to avoid chafing	a simple machine consisting of a wheel with a groove in which a rope can run to change the direction or point of application of a force applied to the rope