mouse is géri

géri = mouse
alternate spelling: gehri

Some things Google found for "geri":
Geri is an uncommon feminine first name which can be short for Geraldine. Geri is an unusual last name. In Turkish geri means back, rear, reverse. In Portuguese a form of the verb to manage, to administer. Geri is the name of places in Turkey, Sudan, Georgia, Indonesia, Nigeria, Pakistan, and Russia.

Word derivation for "mouse" :
Hungarian = egér
Finnish = hiiri (which I transliterate to híri)
Samgur = géri

bear is madu

madu = bear
alternate spelling: maduh

Some things Google found for "madu":
Madu is an unusual to uncommon last name. Madu is an unusual masculine first name. In Indonesian madu means honey. In Estonian madu means snake. Madu Station is a station on the Seoul Subway Line 3 in South Korea. Madu is the name of places in China, Indonesia, South Korea, Mozambique, and Sierra Leone.

Word derivation for "bear" :
Hungarian = medve
Finnish = karhu
Samgur = madu

This Samgur word takes consonants from the Hungarian word, and vowels from the Finnish word.

snow is loy

loy = snow

Some things Google found for "loy":
Loy is an unusual to uncommon masculine first name. Loy is an uncommon last name, notably actress Myrna Loy. A loy is an Irish spade used for manual plowing (or ploughing). Loy is the name of places in Germany and in the US in Arkansas.

Word derivation for "snow" :
Hungarian = hó
Finnish = lumi
Samgur = loy

I decided to include several diphthongs in Samgur. I dropped the accent from the O in the Hungarian word, added it to the I in the Finnish word to get OI, then transliterated OI to OY.

forest is mersö

mersö = forest
alternate spelling: merseu

Some things Google found for "merso":
Merso is an unusual to rare last name. Merso is a rare first name. Merso Art School in Greece. In Latin merso means I immerse. Merso Soprano is the name of a place in Italy.

Word derivation for "forest" :
Hungarian = erdő (which I transliterate to erdö)
Finnish = metsä
Samgur = mersö

lake is tója

tója = lake
alternate spelling: tohya

Some things Google found for "toja":
Toja is an unusual last name. Toja is a rare feminine first name. Isla de La Toja is an Spanish island in Galicia. La Toja is the name of places in Spain. Toja Jahuir Guano is the name of a place in Boliva.

Word derivation for "lake" :
Hungarian = tó
Finnish = järvi
Samgur = tója

Making this word, I changed the ä to a for vowel harmony.

Tója replaces toyä as the Samgur word for lake. I've decided to not transliterate j to y.

river is jofi

jofi = river
alternate spelling: yofi

Some things Google found for "jofi":
Jofi is an unusual first name. Jofi is an unusual to rare last name. Salon Jofi in West Orange, New Jersey.

Word derivation for "river" :
Hungarian = folyó (which I transliterate to foyjó)
Finnish = joki
Samgur = jofi

Jofi replaces koyó as the Samgur word for river. I've decided not to transliterate j to y.

mountain is vordy

vordy = mountain
alternate spelling: vorj

Some things Google found for "vordy":
Vordy is a rare first name. Vordy is a rare last name. Domaine Vordy Mayrannes Winery in Languedoc region of France.

Word derivation for "mountain" :
Hungarian = hegy (which I transliterate to hedy)
Finnish = vuori
Samgur = vordy

Note: the dy in vordy is pronounced similar to the dy in Goodyear.