1. start doing something quickly and without prior preparation
I don't want to dive/plunge/jump headlong into anything
If you ‘dive’, ‘plunge’ or ‘jump’ ‘headlong’ into something you become immersed in it straight away or involved in something without any caution or reservation. These expressions can have a positive connotation of getting ‘stuck into’ something that needs to be done without distractions or delay. They can also be used in situations where you want to highlight someone’s recklessness or failure to identify risks. You are more likely to hear these used in situations requiring a professional or personal decision.