Depends which movement called the IRA we're talking about and (more generally) what's meant by "terrorism". There's a degree of a difference between the tactical approach of IRA that won the independence of the Irish Free State in the early twentieth century through classic guerrilla warfare tactics aimed at weakening British security forces and making Ireland ungovernable and and some of the more stereotypical terrorist activities carried out by the Provisional IRA in the late twentieth century involving the high profile bombing of city centres with the (wholly unsuccessful) aim of weakening the British public's resolve to continue to support the Union in Northern Ireland.