together

Examples-

codirector - direct together
coexist - exist together 

treatment

Examples-

~ spelling~ therap   =   therap    +    vowel

 therapist – one who practices treatment
 biotherapy - treatment of life

having to do with

Examples-

bicephalous - having two heads
religious - having to do with religion

heart

Examples-

cardiologist - expert in the  study of the heart
cardioid - resembling the heart

under/below

Examples-

subfloor - the floor underneath                                         substandard – below the standard

side

Examples-
unilateral - one sided
unilateralism - the belief in one side

bad (abnormal / evil)

Examples-

~ spelling        caco    =     cac + vowel

cacogastric - having to do with a bad stomach
cacophony – bad sounds