ノーマーク
nōmāku

Noun
no-Adjective

1. not under observation; not on one's radar; unnoticed

よりによって相手 あいてがノーマークのスーちゃんなんて。
yoriniyotte aitega nōmākuno sūchannante.
That it be with the off-the-radar Sue of all people!

From English "no mark"

Noun
no-Adjective

2. unmarked (player); unguarded; uncovered

Sports
Noun
no-Adjective

3. unmarked (item, etc.); without a mark

Other forms: