member vs pecker

member and pecker both are nouns.

Word	Noun	Adjective	Verb	Adverb
member	Yes	No	No	No
pecker	Yes	No	No	No

As nouns, pecker is a hyponym of member; that is, pecker is a word with a more specific, narrower meaning than member:

Other hyponyms of member include cock, dick, prick, putz, shaft, tool, micropenis, microphallus, erection, hard-on.

member (noun)	pecker (noun)
an external body part that projects from the body	bird with strong claws and a stiff tail adapted for climbing and a hard chisel-like bill for boring into wood for insects
the male sex organ	horny projecting mouth of a bird
an organization that is a member of another organization (especially a state that belongs to a group of nations)	obscene terms for penis
one of the persons who compose a social group (especially individuals who have joined and participate in a group organization)
anything that belongs to a set or class