Delay by putting the date in wrongly (6)
I believe the answer is:
detain
'delay by' is the definition.
'detain' can be an answer for 'delay' (synonyms). I'm not sure about the 'by' bit.
'the date in wrongly' is the wordplay.
'wrongly' is an anagram indicator.
'date'+'in'='datein'
'datein' with letters rearranged gives 'DETAIN'.
'putting' is the link.
Can you help me to learn more?
(Other definitions for detain that I've seen before include "Hold (someone) back" , "Hold in detention" , "Hold back - arrest" , "Delay or take into custody" , "Keep in custody; hold back" .)