Loud child oddly easily understood (5)
I believe the answer is:
lucid
'easily understood' is the definition.
(I've seen this in another clue)
'loud child oddly' is the wordplay.
'oddly' indicates alternate letters (letters in the odd-numbered positions are used).
'loud'+'child'='loudchild'
The alternating letters of 'loudchild' are 'LUCID'.
(Other definitions for lucid that I've seen before include "Clearly presented and easily understood" , "Clear, intelligible" , "Clear; making sense" , "Easily understood; sane" , "Sensible" .)