Dumbo: Disney’s brainchild initially bringing in little? (5)
I believe the answer is:
dweeb
'dumbo' is the definition.
'disney's brainchild initially bringing in little?' is the wordplay.
'initially' indicates taking the first letters.
'bringing in' indicates putting letters inside.
'little?' becomes 'wee' ('wee' can be similar in meaning to 'little').
The initial letters of 'disney brainchild' is 'db'.
'db' placed around 'wee' is 'DWEEB'.
(Other definitions for dweeb that I've seen before include "misfit" , "Insignificant student" , "anorak" , "Boringly studious student" , "(US) idiot" .)