September 2007: INADVERTENT

Adjective – unintentional; inattentive, Noun – inadvertence, Adverb – inadvertently
Oxford Dictionary

Adjective: without intention (especially resulting from heedless action)
Example: “With an inadvertent gesture she swept the vase off the table”
Rhymezone.com

Function: adjective
Etymology: back-formation from inadvertence

1. not focusing the mind on a matter : inattentive
2. unintentional; an inadvertent omission – inadvertently – adverb

Merrium-Webster Online