safe tile (mahjong)
In mahjong, a tile that can be discarded with little risk of giving an opponent an advantage.
I discarded a safe tile and managed to get by for the moment.
safe choice; no-risk option; easily handled person
Idiomatic extension from mahjong: a person or thing that poses no risk or is easy to deal with. Often used for a safe romantic partner or a low-risk decision.
He's a safe choice, so I feel comfortable introducing him.
This plan is a no-risk option; there's no worry about it failing.