Suffer strain, curable only partly (5)
I believe the answer is:
incur
'suffer' is the definition.
(I've seen this before)
'strain curable only partly' is the wordplay.
'only partly' says the answer is hidden in the clue.
'INCUR' can be found hidden inside 'strain curable'.
(Other definitions for incur that I've seen before include "Arouse" , "Bring something on oneself, often unpleasant" , "Lay oneself open to" , "Become liable to (something) through one's actions" , "Sustain" .)