how to remove a .wsp solution i try from central admin>system settings>manage farm solution selected a solution and selected Retracting still this status shown Restract.
how to completely remove this solution.
Their are two ways to completely remove it.
Use Central admin.
Use PowerShell
[Uninstall-SPSolution][1] –Identity SPSoltion.wsp
[Remove-SPSolution][1] –Identity SPSolution.wsp
At the end, if you solution has a timer job, then you need to restart the timer job as well.
To completely remove a solution:
If you're stuck at step #3 with a status frozen on "Retracting", you can try the following in a SharePoint PowerShell console (on all servers of the farm):
Net Stop SPAdminV4
Start-SPAdminJob
Net Start SPAdminV4