### Clue: Hard going over slippery cove – untrustworthy sort (4)
### Answer: HEEL 
 ### Explanation: Definition: untrustworthy sort
 H(abbrev. for "hard") **placed above**(going over, in a down clue) EEL(an untrustworthy man;a slippery cove).
Defn: …, like a slippery cove.
I'm hard-pressed to find an example of "h" as an abbrev. for "hard", except in combination, eg. "hard disc drive".