Inclined to be guarded (6)
I believe the answer is:
tended
'inclined' is the definition.
('tend' can be a synonym of 'incline')
'be guarded' is the wordplay.
'be' becomes 'tend' (tending is a kind of being).
'guarded' becomes 'ed' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tend'+'ed'='TENDED'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for tended that I've seen before include "Cared for or looked after" , "Inclined or leaned towards" , "Took care of, had certain inclination" , "Was apt" , "Had leaning toward, or looke after" .)