This is the 9980th most frequent French word.
full
The word "full" is not French; it is English. In French, similar concepts are expressed with words like "plein" (full in terms of capacity) or "complet" (complete/full in scope).
'pleine' is the feminine adjective form of 'full' indicating that the bottle contains the maximum amount of liquid.
La bouteille est pleine.
The bottle is full.
'comble', in this context, is used as an adjective synonymous with 'full' to refer to a place filled to capacity.
Cet événement a attiré une salle comble.
This event attracted a packed room.
'plein de' is an idiomatic expression pairing 'full' with an abstract concept, like 'gratitude', to indicate being overwhelmed by a strong feeling.