Bitter melon is very bitter; salting it first helps a little.
Tips
usage
苦味 is the noun; to say something tastes bitter, use the adjective: 很苦. The same 味 names the other tastes: 甜味, 酸味, 咸味, 辣味. Figuratively it is the bitterness of hardship, as in 生活的苦味 "the bitter side of life".