Plant that may destroy a toilet? (8)
I believe the answer is:
Here is my best explanation:
'plant that may destroy a' is the definition.
The answer and definition can be both plants as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'toilet?' is the wordplay.
I cannot really understand how this works, but
'toilet?' could be 'lav' ('lav' can be a synonym of 'toilet') and 'lav' is found in the answer.
This explanation may well be incorrect...
(Other definitions for lavender that I've seen before include "Mauvish blue; shrub", "Fragrant plant", "Plant used in perfumery", "Fragrant purple flower used to scent linen etc", "it should smell nice", "fragrant plant", "aromatic shrub", "Shrub with fragrant purple flowers, used to scent linen", "Delicate perfume from shrub with purple leaves" and "Lilac".)