Detectives order foolish individuals around? That's irregular (9)
I believe the answer is:
spasmodic
'irregular' is the definition.
(thesaurus)
'detectives order foolish individuals around?' is the wordplay.
'detectives' becomes 'cid' (abbreviation for Criminal Investigation Department).
'order' becomes 'om' (Order of Merit).
'foolish individuals' becomes 'saps'.
'around?' shows that the letters should be reversed in order (I've seen 'around' mean this).
'cid'+'om'+'saps'='cidomsaps'
'cidomsaps' written backwards gives 'SPASMODIC'.
'that's' is the link.
(Other definitions for spasmodic that I've seen before include "fitfully" , "Done in short bursts" , "Occurring in irregular bursts" , "Occasional" , "Done in brief irregular bursts" .)