The word "learner" is a noun. It refers to someone who is acquiring knowledge or skills in a particular subject or activity.

Which course must first-time drivers in Florida take to be eligible for their Learner License?

You need your learner's licence for a full year, but in that time you must have logged and recorded 100 hours of driving practice.

There are four main things that any language learner need-Motivation, Good resources, Time, Discipline.

a naturalistic learner is someone who learns the language at the same time as learning to communicate in it

source: Second Language Acquisition-Rod Ellis