Since the 1890s and beginning in France, libertarianism has often been used as a synonym for anarchism and its use as a synonym is still common outside the United States.
sˈɪns ðə wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd nˈaɪnti z ænd bɪɡˈɪnɪŋ ɪn fɹˈæns, lˌɪbɚtˈɛɹiənˌɪzəm hɐz ˈɔfən bˌɪn jˈuːzd æz ɐ sˈɪnənˌɪm fɔːɹ ˈænɚkˌɪzəm ænd ɪts jˈuːs æz ɐ sˈɪnənˌɪm ɪz stˈɪl kˈɑːmən aʊtsˈaɪd ðə juːnˈaɪɾᵻd stˈeɪts.