Can you think of three examples of words which are opposites (or near opposites) and differ by the same single letter?

HINTS:
#1: The single letter that changes each word to its opposite is
       the first letter of the longer word.
#2: The extra letter is C.
#3: Synonyms: STAY CLOSE
                         IN PLAIN SIGHT
                         ENCHANT
Answers:

LEAVE -CLEAVE
OVERT - COVERT
HARM - CHARM