Lonely is the opposite of Crowd. Crowd is related to Riot. Riot is related to Upset. Upset is a synonym of Unhappy. 
Spot is a synonym of Glimpse. 
Lonely <--Antonym--> Crowd <--RelatedTo--> Riot <--RelatedTo--> Upset <--Synonym--> Unhappy 
Spot <--Synonym--> Glimpse 