AND if you know Spanish and Esperanto, you will see the connection with "conejo" and "kuniklo" respectively!
So I had to look that up because in the US coney is a fish and I assumed that is where Coney Island in NYC got it's name from. It looks like it was named when that area was still New Amsterdam and was actually named for rabbits not fish.
Which means we can also add konijn to the list.
Listen to the vowel sounds. 'Glass' has a short vowel sound (sounds similar to the English word 'glass' (think of how the Americans say 'glass', but don't say 'gless' like an American would) Say 'glass' with an 'A' and not with an 'E' like in American English), and 'glas' has a long vowel sound (sounds similar to the English word 'gloss').
To help you, use Forvo or Google Translate for audio.