There are 209 4-letter words starting with M in the ENABLE dictionary — 5% of all 3,903 words at this length. M is a one-point tile, so the value in this list is positional rather than numerical — which of these you can play depends far more on where it fits the board than on what it scores.
The list divides into 7 groups by second letter, the largest being the 56 words with ma. Scanning the right group is faster than reading the whole list, which is why it is broken up below rather than run alphabetically.
If you know more than one letter, this page stops being the fast way to find it. Enter what you have in the unscrambler — the Contains, Starts with and Ends with filters combine, and setting both length fields to 4 narrows this list to the handful your letters actually allow.
All 209 words, by second letter
MA… (56)
maar mabe mace mach mack macs made mads maes mage magi mags maid mail maim main mair make mako male mall malm malt mama mana mane mano mans many maps marc mare mark marl mars mart mash mask mass mast mate math mats matt maud maul maun maut mawn maws maxi maya mayo mays maze mazy
ME… (30)
mead meal mean meat meed meek meet meld mell mels melt memo mems mend meno menu meou meow mere merk merl mesa mesh mess meta mete meth mewl mews meze
MH… (1)
mhos
MI… (39)
mibs mica mice mick midi mids mien miff migg migs mike mild mile milk mill milo mils milt mime mina mind mine mini mink mint minx mire miri mirk mirs miry mise miso miss mist mite mitt mity mixt
MO… (54)
moan moas moat mobs mock mocs mode modi mods mogs moil mojo moke mola mold mole moll mols molt moly mome momi moms monk mono mons mony mood mool moon moor moos moot mope mops mopy mora more morn mors mort mosk moss most mote moth mots mott moue move mown mows moxa mozo
MU… (27)
much muck muds muff mugg mugs mule mull mumm mump mums mumu muni muns muon mura mure murk murr muse mush musk muss must mute muts mutt