G4904 συνεργός (synergós)

KJV renderings: companion in labour, (fellow-)helper(-labourer, -worker), labourer together with, workfellow
Strong's definition: a co-laborer, i.e. coadjutor
Derivation: from a presumed compound of G4862 (σύν) and the base of G2041 (ἔργον);

From James Strong's public-domain dictionaries (G), JSON edition by OpenScriptures (CC-BY-SA). Every dotted-underline word in the text links here.