Take a look at the timekeeper (5)
I believe the answer is:
clock
'the timekeeper' is the definition.
(clock is a kind of timekeeper)
'take a look' is the wordplay.
I cannot really understand how this works, but
'look' could be 'lo' (archaic exclamation meaning 'look!') and 'lo' is present in the answer.
This explanation may well be incorrect...
'at' is the link.
Can you help me to learn more?
(Other definitions for clock that I've seen before include "Notice" , "Watch" , "one displaying speed" , "Striker" , "how to falsify car's mileage" .)