smart

1 smart /ˈsmɑɚt/ adjective
smarter; smartest
1 smart
/ˈsmɑɚt/
adjective
smarter; smartest
Britannica Dictionary definition of SMART
1 
chiefly US
a  : very good at learning or thinking about things : intelligent
— see also street-smart
b  : showing intelligence or good judgment : wise
2 
informal + disapproving : behaving or talking in a rude or impolite way : showing a lack of respect for someone
3 
: very popular : stylish and fashionable — somewhat old-fashioned in U.S. English
4 
: very neat and clean — somewhat old-fashioned in U.S. English
5 
: very quick and energetic
6 
: controlled by computers and able to do things that seem intelligent

smart money

— used to say who or what is expected to win, be successful, etc.

— smartly

adverb

— smartness

noun [noncount]
2 smart /ˈsmɑɚt/ verb
smarts; smarted; smarting
2 smart
/ˈsmɑɚt/
verb
smarts; smarted; smarting
Britannica Dictionary definition of SMART
[no object]
1 
: to feel a sudden sharp pain
2 
: to be upset about something — usually used as (be) smarting

smart off

[phrasal verb] US, informal
: to say rude and irritating things to someone
3 smart /ˈsmɑɚt/ adverb
smarter; smartest
3 smart
/ˈsmɑɚt/
adverb
smarter; smartest
Britannica Dictionary definition of SMART
: in a smart way : smartly