The activity of fishing while on a railway.

Its a combination of "On line fishing"
"Are you doing much today down at the ol' station?"
"I might do some onling, you know."
by CardHandler231 December 18, 2017
onl or ONL is an abbreviation for “oh no lie
by gracerose09 June 14, 2021
Abbreviation for 'online'. Standard text message abbreviation.

Vodafone definition: text message query see which friends are online.
RU ONL? (Are you Online?)
by a1pilot October 6, 2007
Only e-mails
by Hercolena Oliver December 18, 2008
oh newt lord

This is said as an exprestion of shock
by Dannityyyyys July 3, 2022