CSV import (from Excel / Google Sheets) is my go-to for this as well. Added bonus is being able to script things - I have some Python scripts that will do a lot of the hard work for me when making cards for a new language (looking up definitions and example sentences from Wiktionary, adding synonyms / antonyms, etc).
I've put them in a Gist for you: https://gist.github.com/andmikey/4da65e0085104e514286678c431.... The script I run is wiktionary_scraper.py, it assumes you've got a vocab_main.xlsx that contains a "lookup" sheet with the first column being all the words you want to look up. Definitions and related words are put into a new file, vocab_defns.xlsx.
I will warn you - it's not very clean code and mostly based on scripts I'd found on GitHub. It's something I threw together over a summer because I needed to learn a lot of Swedish words very quickly, and my usual Anki-adding methods were too slow. Worked out well, but I do keep meaning to come back to it and make it a proper bit of software...
