I was looking how esperanto did the whole "person with a profession or hobby" thing. I did a few searches in the dictionary and noticed something I would like to discuss with someone. It's the -ega part.

kuri (kur·i)
to run

-ega (eg·a)
considerable, major, great

-isto (ist·o)
(suffix indicating a person with a profession or hobby)

kur·eg·ist·o
a runner

...but...

pentri (pentr·i)
to paint (a portrait, landscape, etc)

pentr·ist·o
a painter

Why is -ega used in one, but not the other? The only thing I can think of is the -ega means at a professional level, but without it, means at a hobbyist level. Like I run a few times a week, but I don't represent my country at it. I paint, but I don't sell my paintings. Is that right?

What about the following...
to kill > a killer
to gamble > a gambler
to play > a player
to swim > a swimmer
to travel > traveller

Thanks.

-eg- suffix intensifies the action, so
kuri = to run, but normally
kuregi = to run like hell

kuregisto = one that runs as fast as he can.

But what would pentregi mean? Maybe painting mountains with red paint, I don't know:

-Paĉjo, rusoj pentregas la lunon ruĝa.
-Ĉu ili jam finpentregis ĝin?
-Jes.
-Do niaj homoj nun alpentru "Coca-Cola" blanke...

I read KUREGISTO as a long distance runner; the "long distance" part being covered by the -EG. Someone who runs short distances (100 yard dash sorts of things) might be a KURISTO.

I can't think of anything that -EG might refer to if you embedded it in PENTRISTO, which is probably why it isn't customarily put there. Perhaps someone that paints really large murals or something.

geo63 makes a good point about -EG meaning "all out effort" as well. I wouldn't argue with that.

to kill > a killer -; asaseno, asasino, mortigulo, murdinto, mortiginto, murdanto
to gamble > a gambler -; vetanto, vetludanto
to play > a player -; ludanto, ludisto
to swim > a swimmer -; naĝanto, naĝisto
to travel > traveller -; vojaĝanto, aventuristo, aventurulo

short distance runner = sprintisto
long distance runner = longdistanculo