Spare
Definition 1 of 5
Pro Tip 1/2
Availability Indication
Use 'spare' to indicate something is available for use or can be given away without causing shortage. Do you have a spare charger I could use?
Pro Tip 2/2
Not Required
'Spare' implies that the item or time is not currently needed and can be used if necessary. We have a spare bedroom if you want to stay overnight.