The answers to each clue below are two words that differ by a single letter, except #5, in which the words differ by two letters.

1. Two five-letter words that both name parts of the body and differ only by their second letter
2. A five-letter word that means batty/scatter-brained and a six-letter word that means a small boat

3. A five-letter word that means restaurants that serve corned beef and pastrami and a six-letter, slang word you might hear in such a place.

4. A five-letter word that can be a fruit/vegetable and a color and a six-letter word that can be a flower and a color.

5. A five-letter word that means quiets or soothes and a six-letter word that means uneasy feelings of doubt or worry (two letters are different)

HINT:
#4: The letters of the two words are scrambled.

Answers:

1. WRIST - WAIST
2. DINGY - DINGHY
3. DELIS - DELISH
4. OLIVE - VIOLET
5. CALMS - QUALMS 

Credit:
#3: Paolo Pasco