Neatly replacing one with daughter, Merry (6)
I believe the answer is:
tiddly
'merry' is the definition.
(both can mean slightly drunk)
I cannot understand how the remainder of the clue works.
(Other definitions for tiddly that I've seen before include "drop of booze could make one this" , "A little drunk" , "Slightly drunk or very small" , "Diminutive - drunk" , "Tiny" .)