foot vs instep

foot and instep both are nouns.

Word	Noun	Adjective	Verb	Adverb
foot	Yes	No	Yes	No
instep	Yes	No	No	No

foot (noun)	instep (noun)
travel by walking	the part of a shoe or stocking that covers the arch of the foot
any of various organs of locomotion or attachment in invertebrates	the arch of the foot
the pedal extremity of vertebrates other than human beings
lowest support of a structure
a support resembling a pedal extremity
the part of the leg of a human being below the ankle joint
(prosody) a group of 2 or 3 syllables forming the basic unit of poetic rhythm
an army unit consisting of soldiers who fight on foot
the lower part of anything
a member of a surveillance team who works on foot or rides as a passenger
a linear unit of length equal to 12 inches or a third of a yard