From machah in the sense of greasing; fat; figuratively, rich -- fatling (one).
see HEBREW machah
H4220. meach
[מֵחַ] noun [masculine] fatling (Phoenician מח fat (adjective ); Late Hebrew מֵיחָא figurative of choice flour); — only plural absolute: מֵיחִים עֹלוֺת Psalm 66:15 burnt offerings of fatlings; so מֵחִים Isaiah 5:17 ("" כְּבָשִׂים) according to Hi Du CheHpt (read חֳרָבוֺת and strike out גָּרִים); most, fat ones, figurative for rich men.