1) Carelessly 2) Imprecisely 3) In a careless way 4) In a heedless way 5) In a negligent manner 6) In a negligent way 7) In a slack manner 8) In a slapdash way 9) Leniently 10) Negligently 11) With negligence 12) Without circumspection 13) Without discipline 14) Without due care 15) Without due diligence 1) Leniently 
• (adv.) In a lax manner.
Lax'ly adverb In a lax manner. 
[adv] - in a permissively lenient manner
leniently adverb in a permissively lenient manner; `he felt incensed that Tarrant should have been treated so leniently given his crime`