UNINTENTIONAL
unintentional, unplanned, unwitting
(adjective) not done with purpose or intent; “an unintended slight”; “an unintentional pun”; “the offense was unintentional”; “an unwitting mistake may be overlooked”
designed, intentional, unintentional
(adjective) done or made or performed with purpose and intent; “style...is more than the deliberate and designed creation”- Havelock Ellis; “games designed for all ages”; “well-designed houses”
Source: WordNet® 3.1
Etymology
Adjective
unintentional (comparative more unintentional, superlative most unintentional)
Not intended or deliberate; inadvertent; unwitting
Synonyms
• incidental, unintended; see also accidental or unintentional
Antonyms
• intentional
Source: Wiktionary