diff --git a/src/net.h b/src/net.h
--- a/src/net.h
+++ b/src/net.h
@@ -1008,8 +1008,21 @@
     // Used for headers announcements - unfiltered blocks to relay
     std::vector<BlockHash> vBlockHashesToAnnounce GUARDED_BY(cs_inventory);
 
-    // Block and TXN accept times
+    /**
+     * UNIX epoch time of the last block received from this peer that we had
+     * not yet seen (e.g. not already received from another peer), that passed
+     * preliminary validity checks and was saved to disk, even if we don't
+     * connect the block or it eventually fails connection. Used as an inbound
+     * peer eviction criterium in CConnman::AttemptToEvictConnection.
+     */
     std::atomic<int64_t> nLastBlockTime{0};
+
+    /**
+     * UNIX epoch time of the last transaction received from this peer that we
+     * had not yet seen (e.g. not already received from another peer) and that
+     * was accepted into our mempool. Used as an inbound peer eviction criterium
+     * in CConnman::AttemptToEvictConnection.
+     */
     std::atomic<int64_t> nLastTXTime{0};
 
     // Ping time measurement:
diff --git a/src/net.cpp b/src/net.cpp
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -962,10 +962,11 @@
     // An attacker cannot manipulate this metric without physically moving nodes
     // closer to the target.
     EraseLastKElements(vEvictionCandidates, ReverseCompareNodeMinPingTime, 8);
-    // Protect 4 nodes that most recently sent us transactions.
-    // An attacker cannot manipulate this metric without performing useful work.
+    // Protect 4 nodes that most recently sent us novel transactions accepted
+    // into our mempool. An attacker cannot manipulate this metric without
+    // performing useful work.
     EraseLastKElements(vEvictionCandidates, CompareNodeTXTime, 4);
-    // Protect 4 nodes that most recently sent us blocks.
+    // Protect 4 nodes that most recently sent us novel blocks.
     // An attacker cannot manipulate this metric without performing useful work.
     EraseLastKElements(vEvictionCandidates, CompareNodeBlockTime, 4);
     // Protect the half of the remaining nodes which have been connected the