Millions implored to be socially responsible during pandemic? (6)
I believe the answer is:
masked
'be socially responsible during pandemic?' is the definition.
(in a face mask)
'millions implored' is the wordplay.
'millions' becomes 'm' (abbreviation).
'implored' becomes 'asked' (implore means to ask or beg).
'm'+'asked'='MASKED'
'to' acts as a link.
(Other definitions for masked that I've seen before include "Disguised, covered" , "Unseen" , "With covered face" , "Blocked out, disguised" .)