Answer:
Adjectives that begin with the letter M:
Macabre
Macaronic
Macedonian
Machiavellian
Macho
Mad
Maddening
Magenta
Maggieish
Magic
Magical
Magnanimous
Magnetic
Magnificent
Main
Majestic
Major
Makeshift
Maladapted
Maladaptive
Maladjusted
Maladroit
Malay
Malaysian
Malcontent
Male
Malefic
Malevolent
Malleable
Malicious
Malignant
Malodorous
Mammalian
Mammoth
Manageable
Manageable
Mandatory
Mangy
Maniacal
Manic
Manifold
Manipulative
Manly
Mannerly
Mannish
Many
Marbled
Marching
Marginal
Maroon
Marsh
Marked
Markedly
Marketable
Marred
Married
Martial
Martian
Marvelous
Masculine
Massive
Master
Masterful
Matchless
Material
Materialistic
Maternal
Mature
Mauve
Mawkish
Maximum
Meager
Mean
Measly
Mechanical
Meddlesome
Mediocre
Mediterranean
Mean
Meaningful
Meaningless
Mean-spirited
Meaty
Measured
Meddling
Medical
Mediocre
Meek
Melancholy
Melodic
Melodious
Mellifluous
Mellow
Melodic
Melted
Memorable
Memorial
Menacing
Mendacious
Menial
Mental
Mentionable
Merciful
Mere
Meretricious
Meritorious
Meromorphic
Merry
Mesmerizing
Messianic
Messy
Methodical
Meticulous
Metric
Mewing
Mexican
Middle
Middle-aged
Middle-class
Middling
Midlife
Miffed
Mighty
Mild
Mile-wide
Militant
Military
Milky
Milled
Mimicking
Mindful
Mindless
Mini
Miniature
Minimalist
Minuscule
Minor
Minty
Minute
Miraculous
Miraculously
Mirrored
Misanthropic
Mischievous
Miscreant
Miserable
Misguided
Misleading
Missing
Misted
Misty
Misunderstood
Moaning
Mobile
Mocking
Modern
Modest
Modish
Moist
Moldy
Momentary
Momentous
Monarchical
Monastic
Mongol
Mongoloid
Monomorphic
Monosyllabic
Monotone
Monotonic
Monotonous
Monstrous
Montanan
Moody
Mopey
Moping
Mopish
Moral
Morbid
More
Moribund
Moorish
Moory
Moroccan
Moronic
Morose
Moldavian
Mosey
Mossy
Mostly
Motherly
Motley
Mottled
Mountainous
Mournful
Mousy
Mouthy
Movable
Moving
Mown
Mucky
Muddled
Muddy
Muffled
Mulish
Multicolored
Multilateral
Multiparous
Multiple
Multi-talented
Multivalent
Mummified
Mundane
Murderous
Murky
Muscular
Mushy
Musical
Musing
Musty
Mute
Muted
Myopic
Myriad
Mysterious
Mystical
Mythical
Meows
Meow
Meowers
Meower
Meowzers
Meowzer
Meowsters
Meowster