Hit the ground running is an idiom that means to start something with a lot of energy and enthusiasm. The crossword solutions for this term are TRIP (4 letters) and SLID (4 letters). TRIP is a verb meaning to stumble or move unsteadily, while SLID is a verb meaning to move smoothly and quickly in a particular direction. Together, these two words can be interpreted as a metaphor for starting something with a lot of energy and enthusiasm, which is the definition of the phrase hit the ground running.