Length kept in check, not bad for a cravat (9)
I believe the answer is:
neckcloth
'a cravat' is the definition.
(neckcloth is a kind of cravat)
'length kept in check not bad' is the wordplay.
'length' becomes 'l'.
'kept in' means one lot of letters goes inside another.
'bad' indicates anagramming the letters.
'check'+'not'='checknot'
'checknot' anagrammed gives 'neckcoth'.
'l' inserted inside 'neckcoth' is 'NECKCLOTH'.
'for' acts as a link.
(Other definitions for neckcloth that I've seen before include "Cravat" , "What could cover Adam's apple" .)