Definition of ferments:
(v) :
To react, using fermentation; especially to produce alcohol by aging or by allowing yeast to act on sugars; to brew.
(n) :
Something, such as a yeast or barm, that causes fermentation.
(v) :
To stir up, agitate, cause unrest or excitement in.
(n) :
A state of agitation or of turbulent change.
(n) :
A gentle internal motion of the constituent parts of a fluid; fermentation.
(n) :
A catalyst.