Grows old, as seen regularly in Tangiers (4)
I believe the answer is:
Here is my best explanation:
'grows old' is the definition.
('age' can be a synonym of 'grow old')
'seen regularly in tangiers' is the wordplay.
'seen regularly in' indicates alternate letters.
The alternate letters of 'tangiers' are 'AGES'.
'as' acts as a link.