Check it's a lizard (7)
I believe the answer is:
monitor
I believe this is a double definition.
'check' is the first definition.
(synonyms)
'a lizard' is the second definition.
(I know that monitor is a type of lizard)
'it's' acts as a link.
(Other definitions for monitor that I've seen before include "Watch - lizard - warship - VDU" , "Sort of lizard" , "record" , "Observe over time" , "A television or computer screen" .)