devil

devil /ˈdɛvl̟/ noun
plural devils
devil
/ˈdɛvl̟/
noun
plural devils
Britannica Dictionary definition of DEVIL
1 
a  the Devil : the most powerful spirit of evil in Christianity, Judaism, and Islam who is often represented as the ruler of hell
b  [count] : an evil spirit
2 
[count] informal
a  : a person who does bad things or causes trouble usually in a way that is not too serious
b  : a person (especially a man) who is lucky, unlucky, etc.
3 
the devil informal — used to make a statement or question more forceful
4 
[singular] informal : something that is very difficult or that causes a lot of trouble
— usually used in the phrase a devil of
— see also the devil to pay at 1pay

be a devil

British, informal
— used to tell someone who is not sure about doing something to go ahead and do it

better the devil you know than the devil you don't

— used to say that it is better to deal with a difficult person or situation you know than with a new person or situation that could be worse

between the devil and the deep blue sea

old-fashioned
: in a situation that is difficult because you must choose between two unpleasant things

go to the devil

informal
— used to forcefully and rudely tell someone to go away and leave you alone

like the devil

informal
1 
: very much
2 
: with a lot of energy and speed

speak/talk of the devil

informal
— used in speech to say that someone you have been talking about has unexpectedly appeared