To overreact seemed not quite nice to dad (5)
I believe the answer is:
panic
'to overreact seemed' is the definition.
I can't judge whether this definition defines the answer.
'not quite nice to dad' is the wordplay.
'not quite' means to remove the last letter (most but not all of the word).
'to' says to put letters next to each other (I've seen this in other clues).
'dad' becomes 'pa' (both can mean one's father).
'nice' with its final letter taken off is 'nic'.
'nic' put after 'pa' is 'PANIC'.
Can you help me to learn more?
(Other definitions for panic that I've seen before include "Frantic fear" , "mass hysteria?" , "Uncontrollable terror, infectious fear" , "Flap" , "Blind fear" .)