A person who you treat and whom
treats you as a friend but if they are given a chance would "cut your throat" or
get one over on you/put themselves first if it would benifit themselves, or they would gain an
advantage over you. Similar to an enemy.
A
Frienemy are most female squash players i.e a person who you travel
the pro squash circuits, hang aroung with each other, share
life stories and rooms but all the time are looking for weaknesses with you to have the edge over you in competition such as spotting your illness/injury are.
You run out of sports drink , your
frienemy will not give you a tiny bit of theirs until they have finished thier competition, even though they have more than they need.