1
to be temperate in;to refrain;to abstain;to hold back;to restrain oneself from excessive ...
あなたは喫煙をひかえるべきです。
You should refrain from smoking.
2
to make notes;to jot down (e.g. phone number)
先生は生徒たちにそれらの単語をノートに控えておくよう指示した。
The teacher told the pupils to write those words down in their notebooks.
3
to be in preparation for;to be in waiting for
彼女は入試を控えて神経質になっていた。
She was nervous before the entrance exam.
4
to be soon;to be in the offing
5
to be in a close relationship (e.g. as a backer, etc.)
あの小売店のバックにはもっと大きな会社がひかえています。
The small retail outlet is only a front for a much larger entity.
Other forms
扣える 【ひかえる】 (rarely used kanji form)