Validation remove threats and errors while verification removes mostly bounces.
Email List Validation: Removal of spamtraps, static bounces, complainers, litigators, duplicates, disposables, departmentals, botclickers, false positives, slow responses, format errors, unicode characters and checks the mail exchange record for numerous warning signs.
Email List Verification: Removal of bounces (hard, transient or soft), vacation emails, challenge responses, replies from list servers, feedback reports, mail block relay, forwarders and false positives.