American measures to imprison old lags (7)
I believe the answer is:
loiters
'lags' is the definition.
'american measures to imprison old' is the wordplay.
I cannot quite understand how this works, but
'measures' could be 'rs' (R is an example) and 'rs' is found within the answer.
'old' could be 'o' (common abbreviation eg in OE for Old English) and 'o' is found within the answer.
The remaining letters 'lite' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for loiters that I've seen before include "Hangs about idly" , "Hangs around" , "dawdles" , "Fails to move on" , "Hangs about with toilers" .)