illness ( disease, sickness, ailment, discomfort, malady ); scan ( examine, look into, investigate, study, analyze ); allow ( let, permit, enable, consent, authorize ); bone ( os, awn ); tissue ( texture, paper napkin ); blood ( lineage, blood relation, kinship ); vessel ( vein, grain ); secure ( safe, reliable, confident, credible, dependable ); expensive ( costly, prively, precious, rich ); necessary ( essential, indispensible, obligatory, required ); worry ( concern, anxiety, fear, care, sorrow, regret ); useful ( helpful, beneficial, good, handy, convenient ); patient ( ill, sick, sufferer ); stage ( phase, grade, process, lap, cycle, degree );