patrol vs patroller

patrol and patroller both are nouns.

Word	Noun	Adjective	Verb	Adverb
patrol	Yes	No	Yes	No
patroller	Yes	No	No	No

patrol (noun)	patroller (noun)
the activity of going around or through an area at regular intervals for security purposes	someone on patrol duty; an individual or a member of a group that patrols an area
a detachment used for security or reconnaissance
a group that goes through a region at regular intervals for the purpose of security

patrol (verb)	patroller (verb)
maintain the security of by carrying out a patrol