Hello Alex:
A "loose" term or a term that is "defined loosely" means that someone uses a word or phrase that is imprecise. It is not used in a "specific" way.
For example, One might ask, in a general way; "What is Life?".
This would be an example of a "loosely" used term, because it has no definition at all.
People generally have some conception of "Life" as the condition of a "living thing"
or "living organism".
However, another person, such as a Scientist, would never use Life in a "loose" way.
He would refer to "life" as the exact definition as the term is used in Science.
Another example of an important word that is used in a "loose" or generalized way is HELP.
People often tell others to "get some help". But that has no specific meaning. It clearly means that some change is needed, but HELP is nonspecific.
The same goes for the common use of metaphysical terms such as POSITIVE or NEGATIVE attitudes. Such terms are not exact. They are sufficient for general usage, but they are not specific things that anyone can define. People might say "Be Positive" or "Be Good" but those are generalizations.
.