Frank's awful heartless cat (6)
I believe the answer is:
direct
'frank's' is the definition.
(I've seen this before)
'awful heartless cat' is the wordplay.
'awful' becomes 'dire' ('dire' can be a synonym of 'awful').
'heartless' means to remove the middle letters.
'cat' with its middle taken out is 'ct'.
'dire'+'ct'='DIRECT'
(Other definitions for direct that I've seen before include "Guide the actors in plays and films" , "Creepy-crawly" , "Following the quickest and shortest path" , "Moving without changing direction or stopping" , "Show someone the way" .)