Fòram na Gàidhlig

I was sitting writing in Gaelic and tried to write the word runner. I realised I have no idea what it should be so I checked out how to form occupations from verbs or nouns. I am still none the wiser.

Ruithiche
Ruithear
Ruitheadair
Fear/Bean ruith

's e ruithiche a th' annam looks right to me.

's e ur beachd??

Am Faclair Beag:

ruitheadair
fir. iol. -ean
runner

ruithear
fir. gin. -eir, iol. -an
runner

Doh, bha mi a' cleachdadh leabhraichean aig an àm agus cha robh mi a' smaointinn idir. Mòran taing poor_mouse

'S e do bheatha, a charaid!

All your attempts are correctly formed, it is then a question of which of these people actually use

So could any of the examples be used or is it a case of just learning the correct form for each occupation?

It's always better to choose the form that people are actually using. Knowing how to make these up is still useful though, in case you can't remember or haven't learned a particular piece of vocabulary yet