Be careful (4,3)
![Ross](/clue/static/ross-mug.min.png)
'be careful' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for look out that I've seen before include "A view of the future" , "as Wenceslas did" , "Be on your guard!" , "Take care" , "Beware!" .)
(Other definitions for play safe that I've seen before include "Avoid risk" , "Act cautiously" , "Body of church" , "Don't take risks - its only a game?" , "Avoid taking risks - in game?" .)