Not all trippers travel fast (3)
I believe the answer is:
rip
'fast' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'not all trippers travel' is the wordplay.
'not all' says the answer is hidden in the clue (only some of the letters).
'RIP' is hidden within 'trippers travel'.
Can you help me to learn more?
(Other definitions for rip that I've seen before include "Letters appended to writing on gravestone" , "Tearaway" , "comment on one passing" , "inscription on tomb" , "cad" .)