Laughed introducing a king? Be careful! (4,4)
I believe the answer is:
take heed
'be careful' is the definition.
(I've seen this before)
'laughed introducing a king?' is the wordplay.
'laughed' becomes 'teheed' (I am not sure about this - if you are sure you should believe this answer much more).
'introducing' means one lot of letters goes inside another (some letters introduced or inserted into others).
'king?' becomes 'K' (abbreviation for king in chess).
'a'+'k'='ak'
'teheed' enclosing 'ak' is 'TAKE HEED'.
Can you help me to learn more?
(Other definitions for take heed that I've seen before include "Pay careful attention" , "Beware" , "Listen and pay attention" .)