Complex sentence: This definition of pick-up line is a form of merging an arrogant "cocky" attitude and being funny into a single pick-up line while being proposed in the most effective way of engaging someone's attention in a social situation.
Split into simpler sentences: This definition of pick-up line is a form of merging an arrogant "cocky" attitude and being funny into a single pick-up line. He proposed this as the most effective way of engaging someone's attention in a social situation.