Intellectual, not big-headed, but rather wet (5)
I believe the answer is:
rainy
'wet' is the definition.
(similar in meaning)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for rainy that I've seen before include "Save your money for this damp day" , "Pluvial" , "The day one saves for" , "Save your money for a . . . . . day - to buy an umbrella?" , "Wet, showery" .)