the action of scrambling up or over rough or steep ground, especially as a leisure activity
登山;越野(尤指休闲活动)。
the sport of racing motorcycles over rough and hilly ground
摩托车越野赛。
the alteration of the speech frequency of a telephone conversation or broadcast transmission so as to make it unintelligible without a decoding device
扰频,倒频(使电话或广播在无解码装置的情况下无法接听)。