Telephonist giving a poor rate of exchange (8)
I believe the answer is:
operator
'telephonist' is the definition.
(I've seen this before)
'giving a poor rate of exchange' is the wordplay.
'giving' says to put letters next to each other.
'of exchange' indicates an anagram (I've seen 'exchange' mean this).
'poor'+'rate' is 'poorrate'.
'poorrate' anagrammed gives 'OPERATOR'.
(Other definitions for operator that I've seen before include "Conductor" , "One using an item of equipment" , "Mechanic" , "Driver" , "Mathematical symbol" .)