A somewhat cold, wet start can be intimidating (3)
I believe the answer is:
cow
'a somewhat cold wet' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'start can be intimidating' is the wordplay.
'start' indicates taking the first letters.
'be intimidating' becomes 'ow' (I can't justify this - if you can you should believe this answer much more).
The first letter of 'can' is 'c'.
'c'+'ow'='COW'
Can you help me to learn more?
(Other definitions for cow that I've seen before include "Intimidate; quadruped" , "Female domestic mammal" , "Unnerve" , "Subdue with threats or force" , "Frighten into submission" .)