On the ground, holding small upright (6)
I believe the answer is:
honest
'upright' is the definition.
(I've seen this before)
'on the ground holding small' is the wordplay.
'ground' is an anagram indicator (grind the letters ).
'holding' is an insertion indicator.
'small' becomes 's' (abbreviation - e.g. clothes size).
'on'+'the'='onthe'
'onthe' is an anagram of 'honet'.
'honet' enclosing 's' is 'HONEST'.
(Other definitions for honest that I've seen before include "Trustworthy or candid" , "Genuine; fair" , "Free of deceit and lies - truly!" , "Upright and fair" , "Fair and square" .)