Wiktionary (https://en.wiktionary.org/) is pretty useful and ad free.
You can use the !wt bang command on duckduckgo to query it directly. It will bring up English definitions of words in other common languages like German.
Ex: !wt Schreibtischtäter brings you to https://en.wiktionary.org/wiki/Schreibtischt%C3%A4ter