Rat positioned in queue for loo (7)
I believe the answer is:
latrine
'for loo' is the definition.
(I have seen 'Military loo' mean 'latrine' so perhaps 'loo' could also mean 'latrine')
'rat positioned in queue' is the wordplay.
I cannot quite see how this works, but
an anagram of 'rat' is 'atr' which is present in the answer.
'in' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for latrine that I've seen before include "public toilet" , "Reliant on military loo" , "office" , "A military lavatory" , "Camp toilet" .)