Some children animated when climbing, get more silly (6)
I believe the answer is:
inaner
'more silly' is the definition.
(I've seen this in another clue)
'some children animated when climbing' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'when climbing' shows that the letters should be reversed in order (in a down clue, letters go up).
'renani' is hidden in the letters of 'children animated'.
'renani' backwards is 'INANER'.
'get' is the link.
(Other definitions for inaner that I've seen before include "What's relatively lemon-like" , "Rather silly" , "More vacuous" , "More empty" , "More stupid" .)