Student or Learner
Usually, "enough" describes a noun before it. So is this an exceptional case or acceptable?
36)See if you can think of something really thoughtful to do for someone, and enjoy it for its own sake. It can be mowing your neighbor’s lawn, or coming home early from work to give your spouse a break from the kids. When you complete your favor, see if you can feel the warmth of knowing you have done something for someone without expecting anything. If you practice, I think you will discover that the feelings themselves are reward enough. What interferes with this peaceful feeling is our expectation of receiving something in return. The solution is to
The postpositive use of adjectival 'enough' is archaic, although, like most archaisms, sometimes used to lend a grand or literary sound to one's prose.
I wouldn't call it archaic myself.
Philo specified the 'adjectival enough' as being archaic.
The adverbial 'enough' is of course alive and well.