as likely as not

Translations
вполне возможно
As likely as not, he will arrive late.
Вполне возможно, что он опоздает.
Definitions
A phrase used to indicate that something has an equal chance of happening or not happening; it suggests a probability of about 50%.
Words
as

adverb
так
likely

adjective
вероятно
as

conjunction
как
not

adverb
не