adverb
for
what?
for
what
reason,
cause,
or
purpose?:
Why
did
you
behave
so
badly?
conjunction
for
what
cause
or
reason:
I
don't
know
why
he is
leaving.
for
which;
on
account
of
which
(usually
after
reason
to
introduce
a
relative
clause):
the
reason
why
he
refused
to go.
the
reason
for
which:
That
is
why
he
returned.
noun, plural whys.
a
question
concerning
the
cause
or
reason
for
which
something
is
done,
achieved,
etc.:
a
child's
unending
hows
and
whys.
the
cause
or
reason:
the
whys
and
wherefores
of a
troublesome
situation.