[1] : The Collaborative International Dictionary of English v.0.48

kissing cousin \kiss"ing cous"in\
   a cousin sufficiently well acquainted to be greeted with a
   kiss; a type of kissing kin.
   pjc

[2] : WordNet (r) 2.0

kissing cousin
     n : a more or less distant relative; familiar enough to be
         greeted with a kiss syn: kissing kin
see also:
kissing kin 

Kissing Cousin >> K Words
Kissing Cousin, definition of term: Kissing Cousin
kissing+cousin_pag1.html

Cousin >> C Words
Cousin, definition of term: Cousin
cousin_pag1.html

Kissing >> K Words
Kissing, definition of term: Kissing
kissing_pag1.html

Second Cousin >> S Words
Second Cousin, definition of term: Second Cousin
second+cousin_pag1.html

First Cousin >> F Words
First Cousin, definition of term: First Cousin
first+cousin_pag1.html