Both /focustarget and /enemysign use the term "current target" in their text command descriptions.
/focustarget
Makes current target your focus target when none specified.
/enemysign
Uses current target when not specified.
It appears that both refer to the same target. However, they actually differ: the former refers to a soft target, while the latter refers to a hard target. It is confusing to use the same term to refer to different targets.

In the placeholder descriptions, the term "current target" refers only to the soft target.
Placeholders
Version: Patch 7.41
<t>, <target>
Displays current target name.
<tt>, <t2t>
Displays target of current target's name.
<targethpp>, <thpp>
Displays current target's HP as a percentage.
Therefore I suppose "current target" is not suitable for referring to the hard target and that different wording should be used.

I posted a bug report on the Japanese forums about these commands and suggested adding "(including soft target)" or "(excluding soft target)" for clarification. The issue has been marked as "fixed", and the Japanese expressions have been updated while the English expressions remain unchanged. The following are literal translations of the original Japanese expressions corresponding to "current target". I don't think the Japanese descriptions have become easier to understand, but they do at least use different wording.

/focustarget (referring to the soft target)
Old: The targeted character
New: The character or object selected as a target

/enemysign (referring to the hard target)
Old: The character currently targeted
New: The character or object currently selected as a target