accidental (n.)
- accessory
- accident
- addendum
- addition
- adjunct
- ado
- appendage
- appurtenance
- auxiliary
- breve
- chance
- chancy
- collateral
- contingency
- contingent
- crotchet
- current
- demisemiquaver
- dependent
- doing
- dominant
- extra
- flat
- happening
- happenstance
- hemidemisemiquaver
- iffy
- incidental
- inessential
- minim
- natural
- nonessential
- note
- odd
- on
- other
- parenthetical
- passing
- quaver
- report
- resultant
- secondary
- semibreve
- semiquaver
- sharp
- spiccato
- subsidiary
- supplement
- tercet
- tone
- triplet
accidental (adj.)
- accessory
- accompanying
- additional
- adjunct
- ado
- adscititious
- adventitious
- afloat
- afoot
- aleatory
- appurtenant
- auxiliary
- casual
- causeless
- chance
- chancy
- circumstantial
- coincident
- coincidental
- collateral
- conditional
- contingent
- current
- dependent
- dicey
- dominant
- extra
- fatal
- flat
- fluky
- fortuitous
- iffy
- inadvertent
- incidental
- indeterminate
- inessential
- lucky
- natural
- nonessential
- occasional
- occurring
- odd
- on
- ongoing
- other
- parenthetical
- passing
- prevailing
- prevalent
- provisional
- random
- resultant
- risky
- secondary
- serendipitous
- sharp
- staccato
- subsidiary
- superfluous
- supplemental
- supplementary
- tone
- unanticipated
- uncaused
- undesigned
- undetermined
- unessential
- unexpected
- unforeseeable
- unforeseen
- unintended
- unintentional
- unlooked-for
- unlucky
- unplanned
- unpredictable
- unpremeditated
- unwitting
