Ichininmae (一人前): one person’s share. The Daijisen dictionary defines it as reaching a passable level in an art or a field of learning. The Nihon Kokugo Daijiten adds: reaching the level of others in a skill, and being good enough to be accepted in that world.
The Heibonsha World Encyclopedia calls it a word of evaluation for a grown adult, or for someone whose skill has reached a set level.