What is the qualitative definition of enthalpy in beginner terms?
In my judgment, it's not worth spending much of your valuable time trying to assign physical significance to the physical property we call Enthalpy.  Enthalpy is just a convenient parameter to work with when we are doing certain types of thermodynamic analysis.  One situation which it is particularly useful for is in applying the first law to open systems in which material is entering and/or leaving the system.  Another is where changes in a closed system are occurring at constant pressure.