5 o'clock shadow
noun /ˌfaɪv əˌklɒk ˈʃædəʊ/
/ˌfaɪv əˌklɑːk ˈʃædəʊ/
(also five o'clock shadow)
[singular]- the dark colour that appears on the chin and sides of a man's face when the hair has grown a little during the day since he shaved in the morning