Impregnable

受精可能な

juseikanou na

(capable of being impregnated)

受胎可能な

jutaikanou na

(capable of being impregnated)

鉄壁

teppeki

(of a fortress or other fortified place: able to withstand all attacks — see also impenetrable, inconquerable, unvanquishable)

鐵壁

(of a fortress or other fortified place: able to withstand all attacks — see also impenetrable, inconquerable, unvanquishable)

難攻不落の

nankoufuraku no

(too strong to be defeated or overcome — see also invincible)