unsurpassable

vaikeakulkuinen, ylittämätön Not surpassable; unable to be surpassed.
1908, w:Kenneth Grahame|Kenneth Grahame, w:The Wind in the Willows|The Wind in the Willows

On either side of them, as they glided onwards, the rich meadow-grass seemed that morning of a freshness and a greenness unsurpassable. Never had they noticed the roses so vivid, the willow-herb so riotous, the meadow-sweet so odorous and pervading.