On the same wavelength
Have the same ideas, interest and opinion about something
Withdrawn
detached, unsocialable
Take off
Quickly become popular
Best friend
A very close friend you trust
Myriad
a vast number, a lot
Stand by
Support someone in hard times
Through thick and thin
In good and bad times
Be on nodding terms
Know somebody just enough to greet them
Void
A large, empty space
Online Friend
someone who you only keep in touch with on the internet
Hit it off
Quickly become friends
Fall out with
Suddenly stop being friends
Viable
Possible to do
Moan and groan
Complain, be dissatisfied
Nostalgia
Happy thoughts or feelings about the past