Reinforce (10)
There are a few possibilities for this:
strengthen
'reinforce' is the definition.
(I know that reinforce is a more specific form of strengthen)
This is the entire clue.
(Other definitions for strengthen that I've seen before include "Brace" , "Toughen up" , "Bolster" , "Fortify" , "rally" .)
'reinforce' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for stiffen that I've seen before include "Grow harder" , "more severe" , "Add starch" , "Steel" , "Become more rigid" .)
'reinforce' is the definition.
(I know that bolster is a more specific form of reinforce)
This is all the clue.
(Other definitions for bolster that I've seen before include "Hold up" , "Support; long pillow" , "Long thick pillow" , "Strengthen - long pillow" , "Prop up with long pillow" .)
'reinforce' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for toughen that I've seen before include "Harden, strengthen" , "Make more robust" , "Add resistance to" , "Strengthen, season" , "Make stronger and hardier" .)