Deliberate hoax by helter-skelter rides (8)
I believe the answer is:
consider
'deliberate' is the definition.
(synonyms)
'hoax by helter-skelter rides' is the wordplay.
'hoax' becomes 'con' ().
'by' is a charade indicator (letters next to each other).
'helter skelter' indicates anagramming the letters.
'rides' anagrammed gives 'sider'.
'con'+'sider'='CONSIDER'
(Other definitions for consider that I've seen before include "Cogitate" , "Look at someone or something thoughtfully" , "Contemplate" , "Deem to be, believe" , "Think about - judge" .)