the context is:
the wine has "weight on the tongue".
Can anybody explain me what it means? Please!!
It is equal to full-bodied, full of winey taste, alcohol present, so it is a positive meaning.
It is the opposite to "thin, not much taste, light in alcohol".

Have a look in the wine dictionary!
(entry: full-bodied)

Kajjo, thank you very much! Now I get it.