1. vigorously (ripping, tearing, scratching, etc.); roughly; with a rip (Onomatopoeia)

2. (eating) with a crunch (Onomatopoeia)

3. stiff; starchy; crisp (Onomatopoeia, usu. adverbially as 〜に)

4. (working) hard; energetically; vigorously; furiously (Onomatopoeia)

5. with a series of loud, repeated sounds (e.g. firing a machine gun, revving an engine); with a lot of (continuous) noise (Onomatopoeia)