Status	Description	Can Send Email?
Deliverable	Valid email	Yes
Undeliverable	Not a valid email	No
Accept-all	Unverifiable	Maybe*
Unknown	Unable to verify	Maybe*

* Maybe - Depending upon the over all list quality and the email service provider you are using, you can decide upon sending mails to these emails. If you are using 3rd party ESP then better to avoid sending to these emails.

Valid

Email address exist and is accepting emails. This is confirmed by communicating via SMTP.
These emails are valid and safe to send mail.

Invalid

Email address do not exist or is not accepting mails. Sending mails will result in bounce.

Accept-all

These addresses are not verifiable, as their mail server accepts both valid and invalid addresses. So we cannot definitively verify.

Unknown

We were unable to definitively verify these emails as their mail servers were not reachable during verification. Unknown addresses are checked multiple times from different locations with varying interval before arriving at this result.

Disposable

These are temporary email address and should not be mailed as there is a very high chance of email bouncing.