Mild; submissive (4)
I believe the answer is:
meek
I believe this is a double definition.
'mild' is the first definition.
(I know that mild can be written as meek)
'submissive' is the second definition.
(I've seen this before)
(Other definitions for meek that I've seen before include "Timid, unassertive" , "Patient and easily imposed upon" , "Humbly compliant" , "inheritors of the earth?" , "Mild and gentle" .)