Accidentally trip near turtle (8)
I believe the answer is:
terrapin
'turtle' is the definition.
(I know that terrapin is a type of terrapin)
'accidentally trip near' is the wordplay.
'accidentally' is an anagram indicator (a chaotic or accidental ordering of the letters).
'trip'+'near'='tripnear'
'tripnear' anagrammed gives 'TERRAPIN'.
(Other definitions for terrapin that I've seen before include "Water tortoise" , "Partner I found for freshwater tortoise" , "Small species of turtle" , "freshwater creature" , "Give out" .)