1. My contact list is long.
2. If you would like my contact list, I can share it (my list of contacts) with you.
3. All of my contacts are artists and musicians.
4, Would you like all of my contacts to contact you?
!. In sentence 1. contact is an adjective modifying 'list.'
2.In sentence 2. contact is also an adjective
3.In sentence 3. contacts are, contacts is a plural noun
4.In sentence 4. contacts, plural noun, to contact, is a verb