This is the 11114th most frequent Catalan word.
sufocar
To suffocate or stifle.
Here, 'sufocar' is used metaphorically, meaning to harm the plants by overwatering.
És important no sufocar les plantes amb massa aigua.
It's important not to suffocate the plants with too much water.
In this context, 'sufocar' is used literally to mean causing a physical condition of impeded breathing.
El fum del foc va començar a sufocar els ocupants de la casa.
The smoke from the fire began to suffocate the occupants of the house.
This usage of 'sufocar' is figurative, referring to suppressing a characteristic or aspect of someone's personality.