Nasty type may thus tiptoe (5)
I believe the answer is:
creep
'tiptoe' is the definition.
(I've seen this in another clue)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for creep that I've seen before include "Move softly and slowly like slangy servile person" , "Move silently and secretly" , "Of plants, to grow along the ground" , "Advance slowly and stealthily" , "Move stealthily or along the ground" .)