Definition of unstep in English:

unstep

verb

[WITH OBJECT]Nautical
  • Detach (a mast) from its step.

    ‘they went into the marsh grass to unstep their masts and dismantle their cannon’
    • ‘If the mast was not unstepped, sailboat owners should check the halyards.’
    • ‘Masts which are only slightly over the minimum bridge clearance might conceivably be arranged with removable upper sections which could be unstepped with the aid of a crane.’

Pronunciation:

unstep

/ʌnstɛp/