Detectives on Roman force thick and tenacious (6)
I believe the answer is:
viscid
'tenacious' is the definition.
(thesaurus)
'detectives on roman force thick' is the wordplay.
I cannot really understand how this works, but
'detectives' could be 'cid' (abbreviation for Criminal Investigation Department) and 'cid' is found within the answer.
'force' could be 'vis' (I've seen this in another clue) and 'vis' is present in the answer.
No letters remain.
This explanation may well be incorrect...
'and' is the link.
Can you help me to learn more?
(Other definitions for viscid that I've seen before include "Having the properties of glue" , "Sticky, gluey" , "Of liquid, thick and gluey" , "Of a consistency like treacle" , "Cohesive and sticky" .)