duskaram
su-duṣkaram — difficult; BG 6.34
su-duṣkaram — impossible to perform; SB 4.8.69
duṣkaram — very difficult; SB 6.4.20
su-duṣkaram — very difficult to perform; SB 6.18.69
su-duṣkaram — an extremely difficult task; SB 8.20.20
parama-duṣkaram — extremely difficult to execute; SB 10.3.36
duṣkaram — impossible to be performed; SB 10.89.30-31
duṣkaram — difficult things; CC Adi 14.1