Fixed firmly (6)
There are a few possibilities for this:
ingrained
'fixed firmly' is the definition.
(mooring is a kind of fixing firmly)
This is all the clue.
(Other definitions for moored that I've seen before include "Fastened with a line or anchored" , "Tied up to berth like ship or boat" , "Secured by rope or cable" , "Of boat, tied up or secured" , "Parked (of a boat)" .)
'fixed firmly' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for braced that I've seen before include "Ready for action" , "Stiff" , "Buttressed" , "Supported, gave firmness to" , "Ready for impact - wearing trouser straps" .)
(Other definitions for ingrained that I've seen before include "Dine in rag (anag.)" , "Deep-rooted" , "Deep-dyed" .)