I can't think of anything sounding even close to prurient, but these might be helpful, even if not to OP directly:
frowsy/frowsty/fusty (having a stale and moldy smell);
fetid (sounds like 'fecund', but describes an extremely foul smell, as of decay).
However, I can think of a phrase that comes close-ish:
go to seed (run to seed)
a. Lit. (For a plant) to grow long enough to produce seed.
Plants like that ought not to be allowed to go to seed.
The lettuce went to seed and we couldn't eat it.
b. Fig. (For a plant or a lawn) to produce seeds because it has not had proper care.
You've got to mow the grass. It's going to seed.
Don't let the lawn go to seed. It looks so—seedy!
Fig. (For something) to decline in looks, status, or utility due to lack of care.
This old coat is going to seed. Have to get a new one.
The front of the house is going to seed. Let's get it painted.
I won't mention rancid, because you must've already thought of it.