Alarm seeing lavatory bowl almost frozen (5)
I believe the answer is:
panic
'alarm' is the definition.
(alarm can mean panic or worry)
'lavatory bowl almost frozen' is the wordplay.
'lavatory bowl' becomes 'pan'.
'almost' means to remove the last letter (almost the whole word is kept).
'frozen' becomes 'ice' (I've seen this in other clues).
'ice' with its last letter removed is 'ic'.
'pan'+'ic'='PANIC'
'seeing' is the link.
(Other definitions for panic that I've seen before include "Contagious fear" , "Great consternation" , "Horror" , "general alarm" , "Greek god" .)