Bestest

2 clues
Top of the line, informally
Childish descriptor of a childhood friend
Similar answers:
Abbes
Abbess
Abbesses
Abes
Abesimpson
Abest
Abruptest
Abtesting
Acesatest
Achievementtest
Acidtest
Acidtests
Acutest
Adobes
Adogsbestfriend
Aerobes
Agnewtestament
Airtests
Alatesthit
Alertest