For me at least a 'theoretical definition' is the specific definition of a theory!, by that I mean it's the saying, or articulation (the definition) of the mechanism behind some effect or observation.
Newton sees an apple for from a tree he starts to think about how and why the apple falls, in his mind he starts to form a theory to explain the observation and effect he has observed.
At some point in that process, he defines (articulates, describes) his theory, that is it is the definition of the theory, that is a part of what we refer to as 'The Scientific Method', The scientific method is the process of observing some effect (like the apple), developing and defining a theory to explain that observation, then calculating the consequences of that theory, and then as a final step comparing your calculations (of consequences) to nature by further experiment and observation.
This is how you show that your theory is either correct or incorrect.
However, in science to do this procedure correctly you have to be very specific in the definition of your theory, if your definition is very vague then you can use almost any observation to 'confirm' your theory is correct.
A soldier or judge or a ship is already its own definition (by definition), the description already defines what you are describing, the definition of a soldier, is a soldier, in practice and in theory it cannot be anything else.
I hope that was some help..