The phrase "jerk down" can be described in many different ways, depending on the context in which it is used. Some possible synonyms for this phrase include "yank down," "pull down abruptly," "tug downwards," "force downwards," as well as "drop suddenly." Other related phrases that convey a similar sense of sudden or forceful downward movement might include "slam down," "bang down," or "crash down." Depending on the tone and intent of the speaker or text, these different synonyms could convey a range of emotions, from frustration or anger to urgency or even excitement.