well working1
/ˈwɛl ˌwəːkɪŋ/noun
Successful activity or operation.
Origin
Mid 16th century (in an earlier sense). Partly from well + working.
well-working2
/ˌwɛlˈwəːkɪŋ/adjective
That works well; operating or functioning properly or efficiently.
Origin
Middle English (in an earlier sense). From well + working.