Strengthen (9)
'strengthen' is the definition.
(reinforcing is a kind of strengthening)
This is all the clue.
(Other definitions for reinforce that I've seen before include "give added support" , "Give added strength to" , "Make stronger" , "Strengthen or support with confrerie" , "provide support" .)
'strengthen' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bolster that I've seen before include "Lobster (anag.)" , "Strengthen - long pillow" , "Extended pillow" , "Reinforce; a cushion" , "Long thick pillow" .)
'strengthen' is the definition.
(synonyms)
This is all the clue.
(Other definitions for fortify that I've seen before include "Increases strength" , "Invigorate, encourage" , "Invigorate; strengthen" , "Make stronger" , "Support" .)
'strengthen' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for anneal that I've seen before include "Heat and cool slowly to toughen, metal or glass" , "toughening process" , "Temper by heat treatment" , "Destress using heat" , "Make tough" .)