One initially dropped? (5)
I believe the answer is:
aitch
'one initially dropped?' is the definition.
I can't judge whether this defines the answer.
'one initially dropped?' is the wordplay.
'one' becomes 'a'.
'initially dropped?' becomes 'itch' (I can't justify this - if you can you should believe this answer much more).
'a'+'itch'='AITCH'
Can you help me to learn more?
(Other definitions for aitch that I've seen before include "Letter sound that's often dropped?" , "Aspirated letter" , "that may be dropped" , "the start of hives?" , "It's dropped by Cockneys" .)