Strong temporary shelter by the river (6)
I believe the answer is:
potent
'strong' is the definition.
(similar in meaning)
'temporary shelter by the river' is the wordplay.
'temporary shelter' becomes 'tent' (I've seen this in another clue).
'by' says to put letters next to each other.
'the river' becomes 'Po' (Italian river).
'tent' put after 'po' is 'POTENT'.
(Other definitions for potent that I've seen before include "Mighty" , "Powerful, influential" , "Forceful" , "Powerful like strong drink" , "Maybe overpowering" .)