-ist

(Greek > Latin: a suffix; one who believes in; one who is engaged in; someone who does something)

modernist
1. An artist who makes a deliberate break with previous styles.
2. A practice, usage, or expression peculiar to modern times.
3. The deliberate departure from past traditions and the use of innovative, or new, forms of expressions which distinguish many styles in the arts and literature of the 20th century.
monarchist
1. Someone who believes in the system or principles of monarchy; especially, a king or queen, who rules a state or territory, usually for life and by hereditary right.
2. A person who has a belief in and who advocates having a monarchy; such as, anyone who reigns over a state or territory, usually for life and by hereditary right; especially, a sole and absolute ruler or a king or empress, often with constitutionally limited authority.
monogamist
A person who is married to just one spouse.
mononeirist
A person who claims to have dreamed just once.
monotheist (s) (noun), monotheists (pl)
Someone who believes that there is only one God and no other gods.
moralist
morphologist
A specialist who does research in the branch of biology that deals with structure and form.

It includes the anatomy, histology, and cytology of the organism at any stage or period of its life history.

municipalist
Someone who believes in the principle or system of home rule.
muralist (s) (noun), muralists (pl)
A person, or people, who paint on flat surfaces or solid partitions: Some muralists expose their artistic talents to pubic criticism by painting on the sides of buildings which were not meant to have such exhibitions.
musicologist
Someone who systematically studies music and musical style, particularly in the realm of historical research.

Today, the scope of musicology for a musicologist may be summarized as covering the study of the history and phenomena of music, including (1) form and notation, (2) biography, (3) the development of musical instruments, (4) music theory (harmony, melody, modes, etc.), and (5) aesthetics, acoustics, and physiology of the voice, ear, and hand.

mycologist
Anyone; such as, a botanist who specializes in the study of fungi.
myriotheist (s) (noun), myriotheists (pl)
Someone who believes in, or maintains the doctrine of, a multitude of gods.
myrmecologist (s) (noun) myrmecologists (pl)
Someone or those who specialize in the study of ants.
myropolist
Someone who sells unguents or perfumery. An unguent is a salve for soothing or healing; an ointment.
mythologist
1. A writer of myths.
2. One who is versed in myths or mythology.