Sedulous
diligent, careful to details
Satiety
lack of hunger, the feeling of being full
To meliorate
to make a situation better or to make someone feel better
Immutable
something which does not change easily
Credulous
someone who believes everything he or she is told
Consternation
extreme fear or terror
To connive
to plan something illegal or immoral
Brazen
an extremely insolent and disrespectful attitude
To feign
to pretend