Can a spell with 'target player' target a player who has hexproof from opponents?

Hexproof from opponents (sometimes called 'hexproof from each opponent') means that the player cannot be the target of spells or abilities controlled by their opponents. This is a variant of the standard hexproof ability, extended to apply at the player level rather than just permanents. CR 702.11 covers hexproof, and CR 702.11e specifically addresses hexproof as it applies to players.

When a spell says 'target player,' it must choose a legal target at the time it is cast. If a player has hexproof from opponents, they are not a legal target for any spell or ability controlled by an opponent. Attempting to target them would be an illegal target selection under CR 601.2c, which requires all chosen targets to be legal at the time of casting.

If hexproof from opponents is somehow granted to a player after a spell has already been cast and legally targeted them, the spell's target becomes illegal by the time it resolves. Under CR 608.2b, the spell is countered by the rules if all its targets are illegal upon resolution.

Example: Your opponent controls a Leyline of Sanctity, which gives them hexproof. You cast Thought Erasure and try to target that opponent with 'target player.' You cannot — they are not a legal target, so you must choose yourself or another legal player, or the spell simply cannot be cast if no legal targets exist.

Note that this protection does not prevent opponents from choosing that player as a non-targeted effect. 'Each player' effects or effects that don't use the word 'target' still affect a player with hexproof from opponents, per CR 702.11a.