sick, feeble, dim, swoon, pass out, fearful, weak, light-headed, timid, ill, more...

vivid, intense, bright, strong, clear

lightheaded, dizzy, blackout, syncope, more...

old, languid, subtle, amorous, soft

hard to see,   barely there,   barely noticeable,   barely visible,   go limp,   barely audible,   hard to hear,   almost invisible,   barely perceptible,   barely noticable