arrowlike, dead straight, direct, even, flat, horizontal, in a line, level, lineal, linear, rectilineal, rectilinear, right, ruler-straight, smooth, straight-cut, straight-front, straight-side, straight, streamlined, true, unbeaten, unbending, unbent, unbroken, unconquered, uncurved, undefeated, undeflected, undeviating, undistorted, uninterrupted, unquelled, unsubdued, unswerving, unturned, unvanquished, upright, vertical