Cornish tourist came across me, back at the front (5)
I believe the answer is:
emmet
'cornish tourist' is the definition.
'emmet' can be an answer for 'tourist' (I've seen this before). I am not sure about the 'cornish' bit.
'came across me back at the front' is the wordplay.
'came across' becomes 'met' ('meet' can be a synonym of 'come across').
'back' shows that the letters should be reversed in order.
'at the front' says to put letters next to each other.
'me' reversed gives 'em'.
'met' after 'em' is 'EMMET'.
Can you help me to learn more?
(Other definitions for emmet that I've seen before include "Dialect word for an ant" , "tourist in Cornwall" , "someone doing the Eden Project?" , "Irish nationalist, Robert (1778-1803)" , "tourist in the South West" .)